diff --git a/backends/native/runtime/vulkan/TODO.md b/backends/native/runtime/vulkan/TODO.md
index 2b6b1de54df..f4c8d3bd7ad 100644
--- a/backends/native/runtime/vulkan/TODO.md
+++ b/backends/native/runtime/vulkan/TODO.md
@@ -14,3 +14,23 @@ HuggingFace Llama 3.2 1B 8da4w, 2K export: peak GPU memory is 2794 MiB, against
 2265 MiB with buffer SDPA disabled and 2263 MiB for the ET-VK `.pte`. The
 +528 MiB comes from enabling buffer SDPA. Give these temporaries lifetimes in
 the memory plan, measure again, and attribute whatever remains.
+
+## Lower int4 weight-only linear for any N
+
+`FuseQuantizedLinear` leaves an int4 weight-only linear unlowered when N is not
+a multiple of 4, to match `VK_CHECK_COND(N % 4 == 0)` in ET-VK's
+`prepack_q4_w_4x8_nc_buffer`, and the engine then rejects the quantized weight.
+Round N up to a multiple of 4 there (the pack shader already fills n >= N with
+zeros) and mask the partial last tile on store. Until then Vulkan fails the op
+sample tests `linear_int4wo_*.linear_feature_sizes_2` and
+`linear_int4wo_*.linear_unbatched_0`, where N is 1 and 43.
+
+## Rank-4 linear input
+
+Vulkan returns wrong outputs for the op sample test
+`linear_float.linear_leading_batch_1`, an `nn.Linear(67, 43)` on a
+(2, 4, 8, 67) input: in f32 the fitted rel_bias is -0.48, and f16 returns
+values up to 6.1e4. Both are consistent with only one of the two outer batches
+being written. The rank-3 inputs (4, 8, 67) and (2, 7, 256) pass. Find where
+the outer dimension is lost: the engine's linear lowering, or ET-VK's linear on
+a rank-4 tensor.