diff --git a/setup.py b/setup.py
index bd59a306172..9d4d6beb491 100644
--- a/setup.py
+++ b/setup.py
@@ -10312,7 +10312,7 @@ def main() -> int:
         else:
             table = hipblaslt_table(gpu["arch"], lib_dirs, meta.get("hipblaslt_version"), [eng / "tuning"])
             if table:
-                cfg["env"] = {"STRATA_HIPBLASLT_TUNING": str(table)}
+                cfg.setdefault("env", {})["STRATA_HIPBLASLT_TUNING"] = str(table)
         if GFX1103_OPT_IN and gfx_arch_is(gpu["arch"], "gfx1103") and not WIN:
             # the 780M's KFD queues are evicted (a GPU reset) while transparent huge pages move the pinned expert arena
             cfg.setdefault("env", {})["STRATA_NO_ARENA_THP"] = "1"
diff --git a/tools/test_setup_unsloth.py b/tools/test_setup_unsloth.py
index 2d32c13976b..ac76aa6e8c6 100644
--- a/tools/test_setup_unsloth.py
+++ b/tools/test_setup_unsloth.py
@@ -286,6 +286,22 @@ def test_amd_is_not_asked(self):
         self.assertNotIn("has not been run on AMD cards yet", out)
         self.assertIn("RAM budget: 40 GiB of UD-Q4_K_XL's experts", out)
 
+    def test_hip_keeps_the_env_of_an_all_ram_install(self):
+        """The hipBLASLt table joined setup's env instead of replacing it: an Unsloth install whose experts all stay
+        in RAM lost STRATA_ROUTE_TAIL_SKIP=0, and the skip costs these files KL (docs/QUANTS.md)."""
+        r9700 = [{"index": 0, "name": "AMD Radeon AI PRO R9700", "vram_gb": 31.9, "arch": "gfx1201",
+                  "driver": "amdgpu"}]
+        table = self.t / "tools" / "hip" / "gfx1201-hipblaslt-100401.txt"
+        with mock.patch.object(setup, "get_prebuilt_hip", lambda *a, **k: self.t / "engine"), \
+                mock.patch.object(setup, "build_engine_hip", lambda *a, **k: self.t / "engine"), \
+                mock.patch.object(setup, "hipblaslt_table", lambda *a, **k: table):
+            code, out, cfg = self.main(["--context", "8192", "--backend", "hip", "--vision", "no"],
+                                       amd=r9700, ram=95.8)
+        self.assertEqual(code, 0, out)
+        self.assertNotIn("--resident-budget-gib", cfg["args"])    # 96 GB holds every expert: no budget, the skip is off
+        self.assertEqual(cfg["env"]["STRATA_HIPBLASLT_TUNING"], str(table))
+        self.assertEqual(cfg["env"]["STRATA_ROUTE_TAIL_SKIP"], "0")
+
     def test_resumed_download_needs_room_for_the_rest_only(self):
         """#425: the disk check counts the finished shards and .part files already there (sizes scaled down: a
         2 MB "model" with 1.5 MB on the disk, 8 GB of other room needed, 8.001 GB free)."""