diff --git a/changelog.d/7485-repsel-4b-field-store-elision.md b/changelog.d/7485-repsel-4b-field-store-elision.md
new file mode 100644
index 0000000000..b88d7eface
--- /dev/null
+++ b/changelog.d/7485-repsel-4b-field-store-elision.md
@@ -0,0 +1 @@
+**Repsel Phase 4b cleanup: dead `PERRY_UNBOXED_OBJECT_FIELDS` prototype deleted.** The Phase 4b (narrow) mandatory items — class-field store note/addref elision on `Ptr<Shape>`-proven receivers (4b.1) and the INT32 layout-poison canonicalization (4b.2) — landed in #6919/#6930; this ships the remaining sanctioned item. The prototype's write path was bit-identical to the default typed-shape path and its read side was never implemented, so the env flag, the hard-coded `{x,y}` object-literal matcher, `js_gc_init_unboxed_object_layout`, `js_object_{get,set}_unboxed_f64_field`, the codegen declarations/`gc_call_effects` entry, and the flag's object-cache/build-cache key entries are gone. The `js_typed_feedback_object_set_unboxed_f64_field` sentinel symbol stays (`check_runtime_symbols.sh` + keepalive-anchor surface, #854 foundation); its guarded fast path now uses the plain indexed setter, which routes through the identical `runtime_store_jsvalue_slot`. GC layout tests that used the prototype installer as a store convenience moved onto the load-bearing `js_gc_init_typed_shape_layout` (`layout_trace/unboxed_object.rs` → `layout_trace/object_layout_invalidation.rs`), preserving the shape-change invalidation coverage (dynamic add / delete / `defineProperty` / accessors) on the default path; prototype-only twins of existing typed-shape tests were dropped. Full gap suite: zero changed outcomes vs a same-session pristine-main baseline (measured twice, before and after rebasing onto #7474's main). The `addr_class` ratchet baseline tightened by the deleted setter's bare-address site.
diff --git a/crates/perry-codegen/src/expr/object_literal.rs b/crates/perry-codegen/src/expr/object_literal.rs
index 5aaf35d26a..43e61327d1 100644
--- a/crates/perry-codegen/src/expr/object_literal.rs
+++ b/crates/perry-codegen/src/expr/object_literal.rs
@@ -11,7 +11,7 @@ use super::temp_root::{
 };
 use super::{lower_expr, nanbox_pointer_inline, FnCtx};
 use crate::nanbox::POINTER_MASK_I64;
-use crate::type_analysis::{compute_auto_captures, is_numeric_expr};
+use crate::type_analysis::compute_auto_captures;
 use crate::types::{DOUBLE, I32, I64, PTR};
 
 fn expected_interface_property_type(
@@ -120,87 +120,6 @@ fn typed_object_literal_layout(
     })
 }
 
-fn unboxed_object_fields_enabled() -> bool {
-    matches!(
-        std::env::var("PERRY_UNBOXED_OBJECT_FIELDS").as_deref(),
-        Ok("1")
-    )
-}
-
-fn is_number_type(ty: &HirType) -> bool {
-    matches!(ty, HirType::Number)
-}
-
-fn object_type_is_exact_xy_number(ty: &perry_hir::types::ObjectType) -> bool {
-    ty.index_signature.is_none()
-        && ty.properties.len() == 2
-        && ty
-            .properties
-            .get("x")
-            .map(|prop| is_number_type(&prop.ty))
-            .unwrap_or(false)
-        && ty
-            .properties
-            .get("y")
-            .map(|prop| is_number_type(&prop.ty))
-            .unwrap_or(false)
-}
-
-fn interface_is_exact_xy_number(iface: &perry_hir::Interface) -> bool {
-    iface.extends.is_empty()
-        && iface.methods.is_empty()
-        && iface.properties.len() == 2
-        && iface
-            .properties
-            .iter()
-            .any(|prop| prop.name == "x" && is_number_type(&prop.ty))
-        && iface
-            .properties
-            .iter()
-            .any(|prop| prop.name == "y" && is_number_type(&prop.ty))
-}
-
-fn expected_type_is_exact_xy_number(ctx: &FnCtx<'_>, expected_ty: &HirType, depth: usize) -> bool {
-    if depth > 32 {
-        return false;
-    }
-    match expected_ty {
-        HirType::Object(obj) => object_type_is_exact_xy_number(obj),
-        HirType::Named(name) => {
-            if let Some(alias) = ctx.type_aliases.get(name) {
-                if expected_type_is_exact_xy_number(ctx, alias, depth + 1) {
-                    return true;
-                }
-            }
-            ctx.interfaces
-                .get(name)
-                .map(interface_is_exact_xy_number)
-                .unwrap_or(false)
-        }
-        _ => false,
-    }
-}
-
-fn unboxed_xy_object_literal(
-    ctx: &FnCtx<'_>,
-    props: &[(String, Expr)],
-    expected_ty: Option<&HirType>,
-) -> bool {
-    if !unboxed_object_fields_enabled() {
-        return false;
-    }
-    if props.len() != 2 || props[0].0 != "x" || props[1].0 != "y" {
-        return false;
-    }
-    let Some(expected_ty) = expected_ty else {
-        return false;
-    };
-    expected_type_is_exact_xy_number(ctx, expected_ty, 0)
-        && props
-            .iter()
-            .all(|(_, value_expr)| is_numeric_expr(ctx, value_expr))
-}
-
 fn emit_object_mask_global(ctx: &mut FnCtx<'_>, kind: &str, mask_words: &[u64]) -> String {
     if mask_words.is_empty() {
         return "null".to_string();
@@ -253,13 +172,6 @@ fn emit_object_typed_shape_init(
     );
 }
 
-fn emit_unboxed_object_layout_init(ctx: &mut FnCtx<'_>, obj_handle: &str) {
-    ctx.block().call_void(
-        "js_gc_init_unboxed_object_layout",
-        &[(I64, obj_handle), (I32, "2"), (I64, "3"), (I64, "0")],
-    );
-}
-
 fn is_generator_iterator_object_literal(props: &[(String, Expr)]) -> bool {
     if props.len() != 3 {
         return false;
@@ -343,55 +255,6 @@ pub(crate) fn lower_object_literal(
             )
         });
 
-    if !any_method_closure && unboxed_xy_object_literal(ctx, props, expected_ty) {
-        let mut packed_keys = String::new();
-        for (k, _) in props {
-            packed_keys.push_str(k);
-            packed_keys.push('\0');
-        }
-        let keys_idx = ctx.strings.intern(&packed_keys);
-        let keys_entry = ctx.strings.entry(keys_idx);
-        let keys_global = format!("@{}", keys_entry.bytes_global);
-        let keys_len_str = keys_entry.byte_len.to_string();
-
-        let mut shape_id: u32 = 0x811c9dc5;
-        for b in packed_keys.as_bytes() {
-            shape_id ^= *b as u32;
-            shape_id = shape_id.wrapping_mul(0x01000193);
-        }
-        if shape_id == 0 {
-            shape_id = 1;
-        }
-        let shape_id_str = shape_id.to_string();
-
-        let obj_handle = ctx.block().call(
-            I64,
-            "js_object_alloc_with_shape",
-            &[
-                (I32, &shape_id_str),
-                (I32, &n_str),
-                (PTR, &keys_global),
-                (I32, &keys_len_str),
-            ],
-        );
-
-        let rooted = rooted_handle_begin(ctx, &obj_handle, protect_handle);
-        for (i, (_, value_expr)) in props.iter().enumerate() {
-            let v = lower_expr(ctx, value_expr)?;
-            let idx_str = i.to_string();
-            let obj_handle = rooted_handle_get(ctx, &rooted);
-            ctx.block().call_void(
-                "js_object_set_unboxed_f64_field",
-                &[(I64, &obj_handle), (I32, &idx_str), (DOUBLE, &v)],
-            );
-        }
-        let obj_handle = rooted_handle_get(ctx, &rooted);
-        emit_unboxed_object_layout_init(ctx, &obj_handle);
-        let boxed = nanbox_pointer_inline(ctx.block(), &obj_handle);
-        rooted_handle_release(ctx, rooted);
-        return Ok(boxed);
-    }
-
     if !any_method_closure && field_count > 0 {
         // Build packed keys "k1\0k2\0…" interned in the StringPool (shared
         // across all literals with the same key set + order).
diff --git a/crates/perry-codegen/src/gc_call_effects.rs b/crates/perry-codegen/src/gc_call_effects.rs
index c4474eb66a..78fd678d4b 100644
--- a/crates/perry-codegen/src/gc_call_effects.rs
+++ b/crates/perry-codegen/src/gc_call_effects.rs
@@ -82,7 +82,6 @@ pub(crate) fn classify_direct_callee(name: &str) -> GcCallEffect {
         | "js_gc_note_slot_layout"
         | "js_gc_note_slot_layout_aware"
         | "js_gc_init_typed_shape_layout"
-        | "js_gc_init_unboxed_object_layout"
         // `typed_feedback.rs`: counters/registries only. This intentionally
         // does not include feedback wrappers that perform the actual object
         // get/set operation.
diff --git a/crates/perry-codegen/src/runtime_decls/arrays.rs b/crates/perry-codegen/src/runtime_decls/arrays.rs
index b1e78828cd..52c3d38ce0 100644
--- a/crates/perry-codegen/src/runtime_decls/arrays.rs
+++ b/crates/perry-codegen/src/runtime_decls/arrays.rs
@@ -142,7 +142,6 @@ pub fn declare_phase_b_arrays(module: &mut LlModule) {
     //   js_write_barrier_root_heap_word(child_bits: u64)
     //   js_gc_note_slot_layout(parent_bits: u64, slot_index: u32, value_bits: u64)
     //   js_gc_init_typed_shape_layout(obj: u64, slot_count: u32, raw_f64_mask_words: *const u64, raw_f64_mask_word_count: u32, pointer_mask_words: *const u64, pointer_mask_word_count: u32)
-    //   js_gc_init_unboxed_object_layout(obj: u64, slot_count: u32, raw_f64_mask: u64, pointer_mask: u64)
     module.declare_function("js_write_barrier", VOID, &[I64, I64]);
     module.declare_function("js_write_barrier_slot", VOID, &[I64, I64, I64]);
     module.declare_function("js_write_barrier_root_nanbox", VOID, &[I64]);
@@ -155,12 +154,6 @@ pub fn declare_phase_b_arrays(module: &mut LlModule) {
         VOID,
         &[I64, I32, PTR, I32, PTR, I32],
     );
-    module.declare_function(
-        "js_gc_init_unboxed_object_layout",
-        VOID,
-        &[I64, I32, I64, I64],
-    );
-
     // Array methods (Phase B.12).
     // - js_array_pop_f64(arr) -> f64    (last element, NaN if empty)
     // - js_array_join(arr, sep) -> *mut StringHeader (i64)
diff --git a/crates/perry-codegen/src/runtime_decls/objects.rs b/crates/perry-codegen/src/runtime_decls/objects.rs
index 36a0fa1546..d7cb0557af 100644
--- a/crates/perry-codegen/src/runtime_decls/objects.rs
+++ b/crates/perry-codegen/src/runtime_decls/objects.rs
@@ -87,8 +87,6 @@ pub fn declare_phase_b_objects(module: &mut LlModule) {
     // loop hung forever. Declaring the slot as I64 routes through the
     // same register class the runtime actually reads.
     module.declare_function("js_object_set_field", VOID, &[I64, I32, I64]);
-    module.declare_function("js_object_set_unboxed_f64_field", VOID, &[I64, I32, DOUBLE]);
-    module.declare_function("js_object_get_unboxed_f64_field", DOUBLE, &[I64, I32]);
     module.declare_function("js_object_set_field_by_name", VOID, &[I64, I64, DOUBLE]);
     module.declare_function(
         "js_object_set_field_by_property_id",
diff --git a/crates/perry-codegen/tests/typed_shape_descriptors.rs b/crates/perry-codegen/tests/typed_shape_descriptors.rs
index d154d5317c..598cd51afe 100644
--- a/crates/perry-codegen/tests/typed_shape_descriptors.rs
+++ b/crates/perry-codegen/tests/typed_shape_descriptors.rs
@@ -5,33 +5,6 @@ use perry_hir::{
     ModuleInitKind, Stmt, UpdateOp,
 };
 
-static ENV_LOCK: std::sync::Mutex<()> = std::sync::Mutex::new(());
-
-struct EnvVarGuard {
-    key: &'static str,
-    prev: Option<std::ffi::OsString>,
-}
-
-impl EnvVarGuard {
-    fn set(key: &'static str, value: Option<&str>) -> Self {
-        let prev = std::env::var_os(key);
-        match value {
-            Some(value) => std::env::set_var(key, value),
-            None => std::env::remove_var(key),
-        }
-        Self { key, prev }
-    }
-}
-
-impl Drop for EnvVarGuard {
-    fn drop(&mut self) {
-        match &self.prev {
-            Some(value) => std::env::set_var(self.key, value),
-            None => std::env::remove_var(self.key),
-        }
-    }
-}
-
 fn empty_opts() -> CompileOptions {
     CompileOptions {
         target: None,
@@ -331,10 +304,6 @@ fn assert_typed_feedback_setter_after(ir: &str, start_pos: usize, context: &str)
         ir.contains("js_object_set_field_by_name"),
         "{context} should keep the safe runtime setter as the typed-feedback fallback"
     );
-    assert!(
-        !after_start.contains("call void @js_object_set_unboxed_f64_field"),
-        "{context} should not use the raw unboxed field setter for dynamic mutation"
-    );
 }
 
 fn point_module(name: &str, body: Vec<Stmt>) -> Module {
@@ -936,46 +905,13 @@ fn typed_object_literal_pointer_free_descriptor_precedes_dynamic_mutation() {
     );
 }
 
+// The `PERRY_UNBOXED_OBJECT_FIELDS` prototype was deleted (Phase 4b cleanup):
+// its write path was bit-identical to the default typed-shape path and its
+// read side was never implemented. This test pins the default path the flag
+// used to bypass: exact `{x, y}` number literals go through the shape-cache
+// allocator, indexed setters, and a typed-shape descriptor install.
 #[test]
-fn unboxed_point_literal_gate_on_emits_raw_setters_and_pointer_free_layout() {
-    let _lock = ENV_LOCK.lock().unwrap();
-    let _env = EnvVarGuard::set("PERRY_UNBOXED_OBJECT_FIELDS", Some("1"));
-    let point_ty = object_type(&[("x", Type::Number), ("y", Type::Number)]);
-    let module = point_module(
-        "unboxed_point_on.ts",
-        vec![
-            Stmt::Let {
-                id: 1,
-                name: "p".to_string(),
-                ty: point_ty,
-                mutable: false,
-                init: Some(Expr::Object(vec![
-                    ("x".to_string(), Expr::Number(1.5)),
-                    ("y".to_string(), Expr::Number(2.5)),
-                ])),
-            },
-            Stmt::Return(Some(Expr::LocalGet(1))),
-        ],
-    );
-
-    let ir = ir_for(module);
-    assert!(ir.contains("call i64 @js_object_alloc_with_shape"));
-    assert!(ir.contains("call void @js_object_set_unboxed_f64_field"));
-    assert!(ir.contains("call void @js_gc_init_unboxed_object_layout"));
-    assert!(
-        ir.contains("i32 2, i64 3, i64 0"),
-        "unboxed point layout should install raw f64 slots for x/y and no pointer slots"
-    );
-    assert!(
-        !ir.contains("call void @js_gc_init_typed_shape_layout"),
-        "gate-on exact point literals should use the unboxed layout installer"
-    );
-}
-
-#[test]
-fn unboxed_point_literal_gate_off_uses_existing_typed_shape_path() {
-    let _lock = ENV_LOCK.lock().unwrap();
-    let _env = EnvVarGuard::set("PERRY_UNBOXED_OBJECT_FIELDS", None);
+fn point_literal_uses_typed_shape_path() {
     let point_ty = object_type(&[("x", Type::Number), ("y", Type::Number)]);
     let module = point_module(
         "unboxed_point_off.ts",
@@ -1000,44 +936,4 @@ fn unboxed_point_literal_gate_off_uses_existing_typed_shape_path() {
     assert!(ir.contains("call void @js_gc_init_typed_shape_layout"));
     assert!(ir.contains("@perry_typed_obj_shape_raw_f64_mask_"));
     assert!(ir.contains("constant [1 x i64] [i64 3]"));
-    assert!(!ir.contains("call void @js_object_set_unboxed_f64_field"));
-    assert!(!ir.contains("call void @js_gc_init_unboxed_object_layout"));
-}
-
-#[test]
-fn unboxed_point_dynamic_mutation_still_uses_safe_by_name_setter() {
-    let _lock = ENV_LOCK.lock().unwrap();
-    let _env = EnvVarGuard::set("PERRY_UNBOXED_OBJECT_FIELDS", Some("1"));
-    let point_ty = object_type(&[("x", Type::Number), ("y", Type::Number)]);
-    let module = point_module(
-        "unboxed_point_mutation.ts",
-        vec![
-            Stmt::Let {
-                id: 1,
-                name: "p".to_string(),
-                ty: point_ty,
-                mutable: true,
-                init: Some(Expr::Object(vec![
-                    ("x".to_string(), Expr::Number(1.0)),
-                    ("y".to_string(), Expr::Number(2.0)),
-                ])),
-            },
-            Stmt::Expr(Expr::PropertySet {
-                object: Box::new(Expr::LocalGet(1)),
-                property: "x".to_string(),
-                value: Box::new(Expr::String("heap".to_string())),
-            }),
-            Stmt::Return(Some(Expr::LocalGet(1))),
-        ],
-    );
-
-    let ir = ir_for(module);
-    let layout_pos = ir
-        .find("call void @js_gc_init_unboxed_object_layout")
-        .expect("fixture should install unboxed layout");
-    assert_typed_feedback_setter_after(
-        &ir,
-        layout_pos,
-        "dynamic property mutation after an unboxed layout",
-    );
 }
diff --git a/crates/perry-runtime/src/gc/layout.rs b/crates/perry-runtime/src/gc/layout.rs
index e3f9132bab..397f07ddbc 100644
--- a/crates/perry-runtime/src/gc/layout.rs
+++ b/crates/perry-runtime/src/gc/layout.rs
@@ -988,97 +988,6 @@ pub extern "C" fn js_gc_init_typed_shape_layout(
     }
 }
 
-#[no_mangle]
-pub extern "C" fn js_gc_init_unboxed_object_layout(
-    obj: u64,
-    slot_count: u32,
-    raw_f64_mask: u64,
-    pointer_mask: u64,
-) {
-    let user_ptr = strip_nanbox_user_ptr(obj);
-    let slot_count = slot_count as usize;
-    if user_ptr == 0 || slot_count > 64 {
-        return;
-    }
-    unsafe {
-        let Some(header) = layout_header_for_user(user_ptr) else {
-            return;
-        };
-        if gc_type_layout_slot_kind((*header).obj_type) != GcLayoutSlotKind::ObjectFields {
-            return;
-        }
-        let obj_header = user_ptr as *const crate::object::ObjectHeader;
-        let object_slot_count = (*obj_header).field_count as usize;
-        if object_slot_count != slot_count {
-            layout_set_typed_unknown(header, user_ptr);
-            return;
-        }
-
-        let raw_f64_mask = LayoutSlotMask::Inline(raw_f64_mask);
-        let pointer_mask = LayoutSlotMask::Inline(pointer_mask);
-        if raw_f64_mask.intersects(&pointer_mask, slot_count) {
-            layout_set_typed_unknown(header, user_ptr);
-            return;
-        }
-
-        if slot_count != 0 {
-            let fields = (obj_header as *const u8)
-                .add(std::mem::size_of::<crate::object::ObjectHeader>())
-                as *const u64;
-            for i in 0..slot_count {
-                let bits = *fields.add(i);
-                if raw_f64_mask.contains_slot(i) {
-                    if !layout_raw_f64_bits(bits) {
-                        layout_set_typed_unknown(header, user_ptr);
-                        return;
-                    }
-                    continue;
-                }
-                if layout_pointer_bearing_bits(bits) && !pointer_mask.contains_slot(i) {
-                    layout_set_typed_unknown(header, user_ptr);
-                    return;
-                }
-            }
-        }
-
-        let descriptor = TypedLayoutDescriptor {
-            slot_count,
-            raw_f64_mask,
-            pointer_mask: pointer_mask.clone(),
-        };
-        // #6893: shared shape descriptor before per-object storage.
-        let keys = if shape_layout_keyed_enabled() {
-            object_keys_array_ptr(user_ptr)
-        } else {
-            0
-        };
-        if keys != 0 && shape_install_shared(keys, header, &descriptor) {
-            TYPED_LAYOUTS.with(|m| {
-                m.borrow_mut().remove(&user_ptr);
-            });
-            LAYOUT_SLOT_MASKS.with(|m| {
-                m.borrow_mut().remove(&user_ptr);
-            });
-            return;
-        }
-        TYPED_LAYOUTS.with(|m| {
-            m.borrow_mut().insert(user_ptr, descriptor);
-        });
-        header_set_typed_layout_intact(header);
-        if pointer_mask.is_empty() {
-            set_layout_state(header, GC_LAYOUT_POINTER_FREE);
-            LAYOUT_SLOT_MASKS.with(|m| {
-                m.borrow_mut().remove(&user_ptr);
-            });
-        } else {
-            set_layout_state(header, GC_LAYOUT_SIDE_MASK);
-            LAYOUT_SLOT_MASKS.with(|m| {
-                m.borrow_mut().insert(user_ptr, pointer_mask);
-            });
-        }
-    }
-}
-
 pub(super) unsafe fn layout_rebuild_from_slots_with_policy(
     user_ptr: *mut u8,
     slots: *const u64,
diff --git a/crates/perry-runtime/src/gc/tests/layout_trace.rs b/crates/perry-runtime/src/gc/tests/layout_trace.rs
index 02d286c88f..cee6c1ced7 100644
--- a/crates/perry-runtime/src/gc/tests/layout_trace.rs
+++ b/crates/perry-runtime/src/gc/tests/layout_trace.rs
@@ -2,8 +2,8 @@ use super::super::*;
 use super::support::*;
 mod array_layout;
 mod object_closure_slots;
+mod object_layout_invalidation;
 mod typed_shape;
-mod unboxed_object;
 
 #[test]
 fn test_trace_array_marks_child() {
diff --git a/crates/perry-runtime/src/gc/tests/layout_trace/unboxed_object.rs b/crates/perry-runtime/src/gc/tests/layout_trace/object_layout_invalidation.rs
similarity index 68%
rename from crates/perry-runtime/src/gc/tests/layout_trace/unboxed_object.rs
rename to crates/perry-runtime/src/gc/tests/layout_trace/object_layout_invalidation.rs
index 5ae281d95c..7eda7debef 100644
--- a/crates/perry-runtime/src/gc/tests/layout_trace/unboxed_object.rs
+++ b/crates/perry-runtime/src/gc/tests/layout_trace/object_layout_invalidation.rs
@@ -1,30 +1,16 @@
 use super::*;
 
-#[test]
-fn test_unboxed_object_layout_scans_zero_raw_numeric_fields() {
-    clear_marks();
-    clear_mark_seeds();
-
-    let obj = crate::object::js_object_alloc(0, 2);
-    crate::object::js_object_set_unboxed_f64_field(obj, 0, 1.25);
-    crate::object::js_object_set_unboxed_f64_field(obj, 1, -2.5);
-    js_gc_init_unboxed_object_layout(obj as u64, 2, 0b11, 0);
-
-    assert_eq!(test_layout_pointer_slot_count(obj as usize, 2), Some(0));
-    assert_eq!(test_heap_child_slot_count(obj as *mut u8), 0);
-
-    let valid_ptrs = build_valid_pointer_set();
-    assert!(try_mark_value(
-        POINTER_TAG | (obj as u64 & POINTER_MASK),
-        &valid_ptrs
-    ));
-    test_reset_trace_slot_reads();
-    trace_marked_objects(&valid_ptrs);
-    assert_eq!(test_trace_slot_reads(), 0);
-
-    clear_marks();
-    clear_mark_seeds();
-}
+// This file used to exercise the `PERRY_UNBOXED_OBJECT_FIELDS` prototype's
+// `js_gc_init_unboxed_object_layout` installer. That prototype was deleted
+// (Phase 4b cleanup): its write path was bit-identical to the default
+// typed-shape path and its read side was never implemented. The coverage the
+// file carried for behavior that still exists moved onto the load-bearing
+// `js_gc_init_typed_shape_layout` installer: raw-numeric scan skipping, the
+// copying-minor descriptor transfer, and descriptor invalidation on every
+// shape-changing mutation (dynamic add, delete, defineProperty, accessors).
+// The prototype-only twins (zero-raw-field scan, pointer-write fallback,
+// `layout_transfer` on move) were dropped — `typed_shape.rs` and
+// `object_closure_slots.rs` already pin those paths for the default installer.
 
 #[test]
 fn test_layout_scan_trace_counts_raw_numeric_object_fields() {
@@ -41,8 +27,8 @@ fn test_layout_scan_trace_counts_raw_numeric_object_fields() {
     .expect("test requested GC trace capture");
 
     let obj = crate::object::js_object_alloc(0, 2);
-    crate::object::js_object_set_unboxed_f64_field(obj, 0, 1.25);
-    crate::object::js_object_set_unboxed_f64_field(obj, 1, -2.5);
+    crate::object::js_object_set_field(obj, 0, crate::value::JSValue::number(1.25));
+    crate::object::js_object_set_field(obj, 1, crate::value::JSValue::number(-2.5));
     let raw_mask = [0b11u64];
     js_gc_init_typed_shape_layout(
         obj as u64,
@@ -94,7 +80,11 @@ fn test_layout_scan_trace_counts_mixed_raw_numeric_object_fields() {
     .expect("test requested GC trace capture");
 
     let obj = crate::object::js_object_alloc(0, 2);
-    crate::object::js_object_set_unboxed_f64_field(obj, 0, f64::from_bits(0x1000));
+    crate::object::js_object_set_field(
+        obj,
+        0,
+        crate::value::JSValue::number(f64::from_bits(0x1000)),
+    );
     let child = crate::string::js_string_from_bytes(b"mixed-child".as_ptr(), 11);
     crate::object::js_object_set_field(obj, 1, crate::value::JSValue::string_ptr(child));
     let raw_mask = [0b01u64];
@@ -135,70 +125,6 @@ fn test_layout_scan_trace_counts_mixed_raw_numeric_object_fields() {
     clear_mark_seeds();
 }
 
-#[test]
-fn test_unboxed_object_pointer_write_to_raw_slot_falls_back_and_traces() {
-    clear_marks();
-    clear_mark_seeds();
-
-    let obj = crate::object::js_object_alloc(0, 2);
-    crate::object::js_object_set_unboxed_f64_field(obj, 0, 1.0);
-    crate::object::js_object_set_unboxed_f64_field(obj, 1, 2.0);
-    js_gc_init_unboxed_object_layout(obj as u64, 2, 0b11, 0);
-    assert_eq!(test_layout_pointer_slot_count(obj as usize, 2), Some(0));
-
-    let child = crate::string::js_string_from_bytes(b"unboxed-child".as_ptr(), 13);
-    let child_header = unsafe { header_from_user_ptr(child as *mut u8) };
-    crate::object::js_object_set_field(obj, 0, crate::value::JSValue::string_ptr(child));
-
-    assert_eq!(
-        test_layout_pointer_slot_count(obj as usize, 2),
-        None,
-        "non-number writes to raw f64 slots must deopt to full scanning"
-    );
-
-    let valid_ptrs = build_valid_pointer_set();
-    assert!(try_mark_value(
-        POINTER_TAG | (obj as u64 & POINTER_MASK),
-        &valid_ptrs
-    ));
-    test_reset_trace_slot_reads();
-    trace_marked_objects(&valid_ptrs);
-    assert_eq!(test_trace_slot_reads(), 2);
-    unsafe {
-        assert_ne!((*child_header).gc_flags & GC_FLAG_MARKED, 0);
-    }
-
-    clear_marks();
-    clear_mark_seeds();
-}
-
-#[test]
-fn test_unboxed_object_descriptor_transfers_on_object_move() {
-    clear_marks();
-    clear_mark_seeds();
-
-    let src = crate::object::js_object_alloc(0, 2);
-    let dst = crate::object::js_object_alloc(0, 2);
-    crate::object::js_object_set_unboxed_f64_field(src, 0, 3.0);
-    crate::object::js_object_set_unboxed_f64_field(src, 1, 4.0);
-    js_gc_init_unboxed_object_layout(src as u64, 2, 0b11, 0);
-
-    unsafe {
-        layout_transfer(src as *mut u8, dst as *mut u8);
-    }
-
-    assert_eq!(test_layout_pointer_slot_count(dst as usize, 2), Some(0));
-    crate::object::js_object_set_unboxed_f64_field(dst, 1, 5.0);
-    assert_eq!(test_layout_pointer_slot_count(dst as usize, 2), Some(0));
-
-    let child = crate::string::js_string_from_bytes(b"moved-child".as_ptr(), 11);
-    crate::object::js_object_set_field(dst, 1, crate::value::JSValue::string_ptr(child));
-    assert_eq!(test_layout_pointer_slot_count(dst as usize, 2), None);
-
-    clear_marks();
-    clear_mark_seeds();
-}
-
 #[test]
 fn test_raw_numeric_object_descriptor_transfers_on_copying_minor_and_skips_raw_slots() {
     let _guard = CopyingNurseryTestGuard::new(1);
@@ -206,9 +132,9 @@ fn test_raw_numeric_object_descriptor_transfers_on_copying_minor_and_skips_raw_s
 
     let child = young_leaf();
     let obj = crate::object::js_object_alloc(0, 3);
-    crate::object::js_object_set_unboxed_f64_field(obj, 0, 10.5);
+    crate::object::js_object_set_field(obj, 0, crate::value::JSValue::number(10.5));
     crate::object::js_object_set_field(obj, 1, crate::value::JSValue::from_bits(ptr_bits(child)));
-    crate::object::js_object_set_unboxed_f64_field(obj, 2, -3.25);
+    crate::object::js_object_set_field(obj, 2, crate::value::JSValue::number(-3.25));
     let raw_mask = [0b101u64];
     let pointer_mask = [0b010u64];
     js_gc_init_typed_shape_layout(
@@ -256,7 +182,7 @@ fn test_raw_numeric_object_descriptor_transfers_on_copying_minor_and_skips_raw_s
     );
 }
 
-fn unboxed_point_for_shape_change_test(shape_id: u32) -> *mut crate::object::ObjectHeader {
+fn typed_point_for_shape_change_test(shape_id: u32) -> *mut crate::object::ObjectHeader {
     let packed_keys = b"x\0y\0";
     let obj = crate::object::js_object_alloc_with_shape(
         shape_id,
@@ -264,9 +190,17 @@ fn unboxed_point_for_shape_change_test(shape_id: u32) -> *mut crate::object::Obj
         packed_keys.as_ptr(),
         packed_keys.len() as u32,
     );
-    crate::object::js_object_set_unboxed_f64_field(obj, 0, 1.0);
-    crate::object::js_object_set_unboxed_f64_field(obj, 1, 2.0);
-    js_gc_init_unboxed_object_layout(obj as u64, 2, 0b11, 0);
+    crate::object::js_object_set_field(obj, 0, crate::value::JSValue::number(1.0));
+    crate::object::js_object_set_field(obj, 1, crate::value::JSValue::number(2.0));
+    let raw_mask = [0b11u64];
+    js_gc_init_typed_shape_layout(
+        obj as u64,
+        2,
+        raw_mask.as_ptr(),
+        raw_mask.len() as u32,
+        std::ptr::null(),
+        0,
+    );
     assert_eq!(test_layout_pointer_slot_count(obj as usize, 2), Some(0));
     obj
 }
@@ -290,18 +224,18 @@ fn descriptor_object_with_single_field(
 }
 
 #[test]
-fn test_unboxed_object_dynamic_added_property_falls_back() {
+fn test_typed_object_dynamic_added_property_falls_back() {
     clear_marks();
     clear_mark_seeds();
 
-    let obj = unboxed_point_for_shape_change_test(86_101);
+    let obj = typed_point_for_shape_change_test(86_101);
     let z_key = crate::string::js_string_from_bytes(b"z".as_ptr(), 1);
     crate::object::js_object_set_field_by_name(obj, z_key, 3.0);
 
     assert_eq!(
         test_layout_pointer_slot_count(obj as usize, 3),
         None,
-        "adding a dynamic property must invalidate the exact unboxed shape"
+        "adding a dynamic property must invalidate the exact typed shape"
     );
 
     clear_marks();
@@ -309,18 +243,18 @@ fn test_unboxed_object_dynamic_added_property_falls_back() {
 }
 
 #[test]
-fn test_unboxed_object_delete_falls_back() {
+fn test_typed_object_delete_falls_back() {
     clear_marks();
     clear_mark_seeds();
 
-    let obj = unboxed_point_for_shape_change_test(86_102);
+    let obj = typed_point_for_shape_change_test(86_102);
     let x_key = crate::string::js_string_from_bytes(b"x".as_ptr(), 1);
     assert_eq!(crate::object::js_object_delete_field(obj, x_key), 1);
 
     assert_eq!(
         test_layout_pointer_slot_count(obj as usize, 1),
         None,
-        "delete shifts keys/fields and must invalidate the exact unboxed shape"
+        "delete shifts keys/fields and must invalidate the exact typed shape"
     );
 
     clear_marks();
@@ -328,11 +262,11 @@ fn test_unboxed_object_delete_falls_back() {
 }
 
 #[test]
-fn test_unboxed_object_define_property_falls_back() {
+fn test_typed_object_define_property_falls_back() {
     clear_marks();
     clear_mark_seeds();
 
-    let obj = unboxed_point_for_shape_change_test(86_103);
+    let obj = typed_point_for_shape_change_test(86_103);
     let x_key = crate::string::js_string_from_bytes(b"x".as_ptr(), 1);
     let desc =
         descriptor_object_with_single_field(86_104, b"value", crate::value::JSValue::number(9.0));
@@ -346,7 +280,7 @@ fn test_unboxed_object_define_property_falls_back() {
     assert_eq!(
         test_layout_pointer_slot_count(obj as usize, 2),
         None,
-        "Object.defineProperty must invalidate the exact unboxed shape even for existing keys"
+        "Object.defineProperty must invalidate the exact typed shape even for existing keys"
     );
 
     clear_marks();
@@ -354,11 +288,11 @@ fn test_unboxed_object_define_property_falls_back() {
 }
 
 #[test]
-fn test_unboxed_object_accessor_define_property_falls_back() {
+fn test_typed_object_accessor_define_property_falls_back() {
     clear_marks();
     clear_mark_seeds();
 
-    let obj = unboxed_point_for_shape_change_test(86_105);
+    let obj = typed_point_for_shape_change_test(86_105);
     let x_key = crate::string::js_string_from_bytes(b"x".as_ptr(), 1);
     // #2817: an accessor descriptor's `get` must be callable — a non-function
     // value now throws. Use a real (capture-less) closure as the getter so we
@@ -379,7 +313,7 @@ fn test_unboxed_object_accessor_define_property_falls_back() {
     assert_eq!(
         test_layout_pointer_slot_count(obj as usize, 2),
         None,
-        "accessor descriptors must invalidate the exact unboxed shape"
+        "accessor descriptors must invalidate the exact typed shape"
     );
 
     clear_marks();
diff --git a/crates/perry-runtime/src/gc/tests/layout_trace/typed_shape.rs b/crates/perry-runtime/src/gc/tests/layout_trace/typed_shape.rs
index 0f12a03f41..d7840aff82 100644
--- a/crates/perry-runtime/src/gc/tests/layout_trace/typed_shape.rs
+++ b/crates/perry-runtime/src/gc/tests/layout_trace/typed_shape.rs
@@ -75,7 +75,7 @@ fn test_typed_shape_descriptor_tracks_raw_numeric_slots() {
     clear_mark_seeds();
 
     let obj = crate::object::js_object_alloc(0, 2);
-    crate::object::js_object_set_unboxed_f64_field(obj, 0, 1.5);
+    crate::object::js_object_set_field(obj, 0, crate::value::JSValue::number(1.5));
     crate::object::js_object_set_field(obj, 1, crate::value::JSValue::number(2.5));
     let raw_mask = [0b01u64];
     js_gc_init_typed_shape_layout(
@@ -149,7 +149,7 @@ fn test_typed_shape_descriptor_visible_for_shape_keyed_objects() {
 
     let raw_mask = [0b01u64];
     for object in [first, second] {
-        crate::object::js_object_set_unboxed_f64_field(object, 0, 1.5);
+        crate::object::js_object_set_field(object, 0, crate::value::JSValue::number(1.5));
         crate::object::js_object_set_field(object, 1, crate::value::JSValue::number(2.5));
         js_gc_init_typed_shape_layout(
             object as u64,
@@ -231,7 +231,7 @@ fn test_shape_keyed_typed_layout_survives_layout_transfer() {
         packed.len() as u32,
     );
     let src = crate::object::js_object_alloc_class_inline_keys(0x6964_01, 0, 2, keys);
-    crate::object::js_object_set_unboxed_f64_field(src, 0, 1.5);
+    crate::object::js_object_set_field(src, 0, crate::value::JSValue::number(1.5));
     crate::object::js_object_set_field(src, 1, crate::value::JSValue::number(2.5));
     let raw_mask = [0b01u64];
     js_gc_init_typed_shape_layout(
@@ -281,7 +281,7 @@ fn test_shape_keyed_typed_layout_survives_layout_transfer() {
     // that must NOT take the shared entry with it: an untouched sibling still
     // reads the shape descriptor.
     let sibling = crate::object::js_object_alloc_class_inline_keys(0x6964_01, 0, 2, keys);
-    crate::object::js_object_set_unboxed_f64_field(sibling, 0, 7.5);
+    crate::object::js_object_set_field(sibling, 0, crate::value::JSValue::number(7.5));
     crate::object::js_object_set_field(sibling, 1, crate::value::JSValue::number(8.5));
     js_gc_init_typed_shape_layout(
         sibling as u64,
@@ -312,7 +312,7 @@ fn test_shape_keyed_typed_layout_survives_copying_minor() {
         packed.len() as u32,
     );
     let obj = crate::object::js_object_alloc_class_inline_keys(0x6964_02, 0, 2, keys);
-    crate::object::js_object_set_unboxed_f64_field(obj, 0, 10.5);
+    crate::object::js_object_set_field(obj, 0, crate::value::JSValue::number(10.5));
     crate::object::js_object_set_field(obj, 1, crate::value::JSValue::number(-3.25));
     let raw_mask = [0b01u64];
     js_gc_init_typed_shape_layout(
@@ -359,7 +359,7 @@ fn test_typed_shape_raw_numeric_slots_accept_pointer_like_f64_bits() {
 
     let obj = crate::object::js_object_alloc(0, 2);
     let pointer_like_number = f64::from_bits(0x1000);
-    crate::object::js_object_set_unboxed_f64_field(obj, 0, pointer_like_number);
+    crate::object::js_object_set_field(obj, 0, crate::value::JSValue::number(pointer_like_number));
     let child = crate::string::js_string_from_bytes(b"mixed-child".as_ptr(), 11);
     crate::object::js_object_set_field(obj, 1, crate::value::JSValue::string_ptr(child));
 
@@ -378,7 +378,11 @@ fn test_typed_shape_raw_numeric_slots_accept_pointer_like_f64_bits() {
     assert_eq!(test_layout_pointer_slot_count(obj as usize, 2), Some(1));
 
     let next_pointer_like_number = f64::from_bits(0x2000);
-    crate::object::js_object_set_unboxed_f64_field(obj, 0, next_pointer_like_number);
+    crate::object::js_object_set_field(
+        obj,
+        0,
+        crate::value::JSValue::number(next_pointer_like_number),
+    );
     assert!(
         layout_typed_raw_f64_slot_for_user(obj as usize, 0),
         "raw f64 slots must not be downgraded by numeric payload bits that resemble raw pointers"
@@ -396,7 +400,7 @@ fn test_typed_shape_descriptor_rejects_nanbox_non_number_tags() {
 
     let raw_mask = [0b1u64];
     let obj = crate::object::js_object_alloc(0, 1);
-    crate::object::js_object_set_unboxed_f64_field(obj, 0, 1.5);
+    crate::object::js_object_set_field(obj, 0, crate::value::JSValue::number(1.5));
     js_gc_init_typed_shape_layout(
         obj as u64,
         1,
@@ -416,7 +420,7 @@ fn test_typed_shape_descriptor_rejects_nanbox_non_number_tags() {
     assert_eq!(test_layout_pointer_slot_count(obj as usize, 1), None);
 
     let handle_obj = crate::object::js_object_alloc(0, 1);
-    crate::object::js_object_set_unboxed_f64_field(handle_obj, 0, 2.5);
+    crate::object::js_object_set_field(handle_obj, 0, crate::value::JSValue::number(2.5));
     js_gc_init_typed_shape_layout(
         handle_obj as u64,
         1,
diff --git a/crates/perry-runtime/src/lib.rs b/crates/perry-runtime/src/lib.rs
index 617314833e..fc03817728 100644
--- a/crates/perry-runtime/src/lib.rs
+++ b/crates/perry-runtime/src/lib.rs
@@ -286,9 +286,8 @@ pub use object::js_object_set_field_by_name;
 pub use object::{
     js_object_alloc, js_object_alloc_null_proto, js_object_alloc_with_shape, js_object_entries,
     js_object_get_field, js_object_get_field_by_name, js_object_get_field_by_name_f64,
-    js_object_get_own_field_or_undef, js_object_get_unboxed_f64_field, js_object_keys,
-    js_object_set_field, js_object_set_field_f64, js_object_set_keys,
-    js_object_set_unboxed_f64_field, js_object_values,
+    js_object_get_own_field_or_undef, js_object_keys, js_object_set_field, js_object_set_field_f64,
+    js_object_set_keys, js_object_values,
 };
 pub use promise::{js_is_promise, js_promise_run_microtasks, js_promise_state, js_promise_value};
 pub use promise::{
diff --git a/crates/perry-runtime/src/object/field_get_set.rs b/crates/perry-runtime/src/object/field_get_set.rs
index 497436d078..e523bdba75 100644
--- a/crates/perry-runtime/src/object/field_get_set.rs
+++ b/crates/perry-runtime/src/object/field_get_set.rs
@@ -179,10 +179,9 @@ pub use enumeration::{
     js_object_keys_value, js_object_values, js_object_values_value,
 };
 pub use field_ops::{
-    js_object_free, js_object_get_class_id, js_object_get_field_f64,
-    js_object_get_unboxed_f64_field, js_object_set_field, js_object_set_field_by_index,
-    js_object_set_field_f64, js_object_set_keys, js_object_set_unboxed_f64_field,
-    js_object_to_value, js_value_to_object,
+    js_object_free, js_object_get_class_id, js_object_get_field_f64, js_object_set_field,
+    js_object_set_field_by_index, js_object_set_field_f64, js_object_set_keys, js_object_to_value,
+    js_value_to_object,
 };
 pub use get_field_by_name::js_object_get_field_by_name;
 pub(crate) use get_field_by_name_tail::get_field_by_name_object_tail;
diff --git a/crates/perry-runtime/src/object/field_get_set/field_ops.rs b/crates/perry-runtime/src/object/field_get_set/field_ops.rs
index 07b15cc0c6..edb2770da1 100644
--- a/crates/perry-runtime/src/object/field_get_set/field_ops.rs
+++ b/crates/perry-runtime/src/object/field_get_set/field_ops.rs
@@ -244,71 +244,6 @@ pub extern "C" fn js_object_set_field_f64(obj: *mut ObjectHeader, field_index: u
     js_object_set_field(obj, field_index, JSValue::from_bits(value.to_bits()));
 }
 
-/// Store a raw f64 into an object field slot for the unboxed numeric-field prototype.
-///
-/// This is only intended for construction sites whose static type has already
-/// proven a raw-number slot. Dynamic writes still go through the normal setters,
-/// which deopt the typed descriptor before tracing non-number values.
-#[no_mangle]
-pub extern "C" fn js_object_set_unboxed_f64_field(
-    obj: *mut ObjectHeader,
-    field_index: u32,
-    value: f64,
-) {
-    let obj = {
-        let b = obj as u64;
-        let t = b >> 48;
-        if t >= 0x7FF8 {
-            if t == 0x7FFC
-                || (b & 0x0000_FFFF_FFFF_FFFF) == 0
-                || (b & 0x0000_FFFF_FFFF_FFFF) < 0x10000
-            {
-                return;
-            }
-            (b & 0x0000_FFFF_FFFF_FFFF) as *mut ObjectHeader
-        } else {
-            obj
-        }
-    };
-    if obj.is_null() || (obj as usize) < 0x10000 {
-        return;
-    }
-    unsafe {
-        let gc = (obj as *const u8).sub(crate::gc::GC_HEADER_SIZE) as *const crate::gc::GcHeader;
-        if (*gc)._reserved & crate::gc::OBJ_FLAG_FROZEN != 0 {
-            return;
-        }
-        let stored_field_count = (*obj).field_count;
-        let alloc_limit =
-            std::cmp::max(stored_field_count, crate::object::INLINE_SLOT_FLOOR as u32);
-        if field_index >= alloc_limit {
-            eprintln!(
-                "[PERRY WARN] js_object_set_unboxed_f64_field: OOB write field_index={} alloc_limit={} (field_count={}) obj={:p} class_id={}",
-                field_index, alloc_limit, stored_field_count, obj, (*obj).class_id
-            );
-            return;
-        }
-        let bits = value.to_bits();
-        let fields_ptr = (obj as *mut u8).add(std::mem::size_of::<ObjectHeader>()) as *mut u64;
-        let slot = fields_ptr.add(field_index as usize);
-        crate::gc::runtime_store_jsvalue_slot(
-            obj as usize,
-            slot as usize,
-            field_index as usize,
-            bits,
-        );
-    }
-}
-
-/// Read a raw f64 object field slot used by the unboxed numeric-field prototype.
-#[no_mangle]
-pub extern "C" fn js_object_get_unboxed_f64_field(
-    obj: *const ObjectHeader,
-    field_index: u32,
-) -> f64 {
-    f64::from_bits(js_object_get_field(obj, field_index).bits())
-}
-
 /// Set a field by index with a raw f64 value (for dynamic object creation)
 /// This is a convenience wrapper that takes field_index as u32 and value as f64.
 /// Honors `Object.freeze` and per-key `writable: false` descriptors so codegen
diff --git a/crates/perry-runtime/src/typed_feedback.rs b/crates/perry-runtime/src/typed_feedback.rs
index a2a8d83bc4..03fec4b0ca 100644
--- a/crates/perry-runtime/src/typed_feedback.rs
+++ b/crates/perry-runtime/src/typed_feedback.rs
@@ -2575,7 +2575,12 @@ pub extern "C" fn js_typed_feedback_object_set_unboxed_f64_field(
         object_key_matches_field(obj, key, field_index) && is_plain_number_bits(value.to_bits()),
     );
     if pass {
-        crate::object::js_object_set_unboxed_f64_field(obj, field_index, value);
+        // The `js_object_set_unboxed_f64_field` prototype setter this wrapper
+        // once used was deleted (Phase 4b cleanup) — its store path was
+        // bit-identical to the plain indexed setter. The symbol name stays
+        // (it is a `check_runtime_symbols.sh` sentinel and part of the #854
+        // typed-feedback foundation); only the fast path changed.
+        crate::object::js_object_set_field(obj, field_index, crate::JSValue::number(value));
     } else {
         record_fallback_call(site_id);
         crate::object::js_object_set_field_by_name(obj, key, value);
diff --git a/crates/perry-runtime/src/typed_feedback/tests.rs b/crates/perry-runtime/src/typed_feedback/tests.rs
index bbb17f5019..7465c9d4a1 100644
--- a/crates/perry-runtime/src/typed_feedback/tests.rs
+++ b/crates/perry-runtime/src/typed_feedback/tests.rs
@@ -1653,7 +1653,7 @@ fn typed_feedback_class_field_get_guard_requires_raw_f64_layout_when_requested()
 
     let class_id = 0x7EED_0043;
     let (obj, expected_keys, key_x, receiver) = class_instance(class_id, b"x");
-    crate::object::js_object_set_unboxed_f64_field(obj, 0, 5.0);
+    crate::object::js_object_set_field(obj, 0, crate::JSValue::number(5.0));
     let raw_mask = [0b1u64];
     crate::gc::js_gc_init_typed_shape_layout(
         obj as u64,
@@ -1689,7 +1689,7 @@ fn typed_feedback_class_field_set_guard_requires_raw_f64_value_and_layout() {
 
     let class_id = 0x7EED_0044;
     let (obj, expected_keys, key_x, receiver) = class_instance(class_id, b"x");
-    crate::object::js_object_set_unboxed_f64_field(obj, 0, 1.0);
+    crate::object::js_object_set_field(obj, 0, crate::JSValue::number(1.0));
     let raw_mask = [0b1u64];
     crate::gc::js_gc_init_typed_shape_layout(
         obj as u64,
diff --git a/crates/perry/src/commands/compile/build_cache.rs b/crates/perry/src/commands/compile/build_cache.rs
index 9e534f12b3..a6ed50122d 100644
--- a/crates/perry/src/commands/compile/build_cache.rs
+++ b/crates/perry/src/commands/compile/build_cache.rs
@@ -43,7 +43,6 @@ const BUILD_CACHE_ENV_VARS: &[&str] = &[
     "PERRY_INLINE_SHADOW_SLOT",
     "PERRY_DISABLE_BUFFER_FAST_PATH",
     "PERRY_VERIFY_NATIVE_REGIONS",
-    "PERRY_UNBOXED_OBJECT_FIELDS",
     // #6125: the resolved CPU baseline (promoted from --march / perry.toml
     // [build] by promote_cpu_baseline_env before this probe runs). Flipping
     // it must invalidate the build-level no-op check, not just per-object
diff --git a/crates/perry/src/commands/compile/object_cache.rs b/crates/perry/src/commands/compile/object_cache.rs
index 2c95d380ae..257ac5110a 100644
--- a/crates/perry/src/commands/compile/object_cache.rs
+++ b/crates/perry/src/commands/compile/object_cache.rs
@@ -231,7 +231,7 @@ fn stable_type_key(ty: &perry_hir::types::Type) -> String {
 /// `PERRY_DEBUG_INIT`, `PERRY_DEBUG_SYMBOLS`, `PERRY_LLVM_CLANG`,
 /// `PERRY_WRITE_BARRIERS`, `PERRY_SHADOW_STACK`,
 /// `PERRY_DISABLE_BUFFER_FAST_PATH`, `PERRY_VERIFY_NATIVE_REGIONS`,
-/// `PERRY_UNBOXED_OBJECT_FIELDS`, and `PERRY_TARGET_CPU`. See the env-var
+/// and `PERRY_TARGET_CPU`. See the env-var
 /// block at the bottom of this function for the rationale.
 ///
 /// NOT captured in the key: the host CPU. By default (`PERRY_TARGET_CPU`
@@ -768,8 +768,6 @@ fn compute_object_cache_key_with_env(
     //     changes Buffer/Uint8Array lowering.
     //   - PERRY_VERIFY_NATIVE_REGIONS=1 overrides CompileOptions and must
     //     not be bypassed by a stale cache hit.
-    //   - PERRY_UNBOXED_OBJECT_FIELDS=1 changes object-literal layout
-    //     lowering for exact typed object shapes.
     //   - PERRY_TARGET_CPU (#6125, set directly or promoted from `--march` /
     //     perry.toml `[build] march`/`native_tuning`) changes the clang
     //     `-march`/`-mcpu` tuning flag, i.e. which instruction-set baseline
@@ -833,12 +831,6 @@ fn compute_object_cache_key_with_env(
             .as_deref()
             .unwrap_or(""),
     );
-    h.field(
-        "env_unboxed_object_fields",
-        env_var("PERRY_UNBOXED_OBJECT_FIELDS")
-            .as_deref()
-            .unwrap_or(""),
-    );
     h.field(
         "env_target_cpu",
         env_var("PERRY_TARGET_CPU").as_deref().unwrap_or(""),
diff --git a/crates/perry/src/commands/compile/object_cache/object_cache_tests.rs b/crates/perry/src/commands/compile/object_cache/object_cache_tests.rs
index d2dec5c4f9..1f62918914 100644
--- a/crates/perry/src/commands/compile/object_cache/object_cache_tests.rs
+++ b/crates/perry/src/commands/compile/object_cache/object_cache_tests.rs
@@ -588,7 +588,6 @@ fn key_changes_with_codegen_env_vars() {
         "PERRY_GC_SAFEPOINT_ONLY",
         "PERRY_DISABLE_BUFFER_FAST_PATH",
         "PERRY_VERIFY_NATIVE_REGIONS",
-        "PERRY_UNBOXED_OBJECT_FIELDS",
         "PERRY_TARGET_CPU",
         // Codegen tuning/emission toggles (#6394).
         "PERRY_TYPED_FEEDBACK",
diff --git a/scripts/addr_class_ratchet_baseline.txt b/scripts/addr_class_ratchet_baseline.txt
index e2a54714f3..7d2dcf3009 100644
--- a/scripts/addr_class_ratchet_baseline.txt
+++ b/scripts/addr_class_ratchet_baseline.txt
@@ -109,7 +109,7 @@ handle-floor | crates/perry-runtime/src/object/descriptor_state.rs | 1
 handle-floor | crates/perry-runtime/src/object/descriptors.rs | 2
 handle-floor | crates/perry-runtime/src/object/field_get_set/accessors.rs | 2
 handle-floor | crates/perry-runtime/src/object/field_get_set/enumeration.rs | 4
-handle-floor | crates/perry-runtime/src/object/field_get_set/field_ops.rs | 4
+handle-floor | crates/perry-runtime/src/object/field_get_set/field_ops.rs | 3
 handle-floor | crates/perry-runtime/src/object/field_get_set/get_field_by_name_tail.rs | 3
 handle-floor | crates/perry-runtime/src/object/field_get_set/has_property.rs | 2
 handle-floor | crates/perry-runtime/src/object/field_get_set/ic_miss.rs | 4