diff --git a/DEPLOYMENT.md b/DEPLOYMENT.md
index e71a738..10728fe 100644
--- a/DEPLOYMENT.md
+++ b/DEPLOYMENT.md
@@ -126,7 +126,7 @@ Then install the attention and kernel dependencies:
   git -C deploy/tmp/cutlass checkout dcf215af
   # build only this machine's arch (the default is a 5-arch fat binary —
   # sm_80..120a — which multiplies compile time ~5x); auto-detected:
-  export JOYOMNI_OPS_CUDA_ARCHS=$(python -c "import torch; cc = torch.cuda.get_device_capability(0); print(f'{cc[0]}{cc[1]}a' if cc[0] >= 10 else f'{cc[0]}{cc[1]}')")
+  export JOYOMNI_OPS_CUDA_ARCHS=$(python -c "import torch; cc = torch.cuda.get_device_capability(0); print(f'{cc[0]}{cc[1]}a' if cc[0] >= 9 else f'{cc[0]}{cc[1]}')")
   echo "building joyomni_ops for sm_$JOYOMNI_OPS_CUDA_ARCHS"
   JOYOMNI_OPS_CUTLASS_DIR=$(pwd)/deploy/tmp/cutlass \
     python -m pip install --no-build-isolation ./deploy/joyomni_ops
diff --git a/deploy/joyomni_ops/setup.py b/deploy/joyomni_ops/setup.py
index 2b6d083..df31a5b 100644
--- a/deploy/joyomni_ops/setup.py
+++ b/deploy/joyomni_ops/setup.py
@@ -9,7 +9,7 @@
   - fp8_scaled_mm                : FP8 per-token x per-channel scaled GEMM (cutlass)
 
 GPU arch coverage is chosen from the local nvcc version:
-  - always: sm_80, sm_89, sm_90
+  - always: sm_80, sm_89, sm_90a
   - CUDA >= 12.8: also sm_100a (B200) and sm_120a (RTX PRO 6000 / RTX 5090)
 So building on a CUDA 12.8+ toolchain automatically yields Blackwell support.
 """
@@ -57,7 +57,12 @@ def _gencodes():
     flags = [
         "-gencode=arch=compute_80,code=sm_80",
         "-gencode=arch=compute_89,code=sm_89",
-        "-gencode=arch=compute_90,code=sm_90",
+        # Hopper must be sm_90a: fp8_scaled_mm selects cutlass'
+        # KernelTmaWarpSpecializedPingpongFP8FastAccum, whose WGMMA path is
+        # arch-conditional. Built as plain sm_90 it compiles and loads, then
+        # aborts every launch ("Arch conditional MMA instruction used without
+        # targeting appropriate compute capability").
+        "-gencode=arch=compute_90a,code=sm_90a",
     ]
     if (mj, mn) >= (12, 8):
         flags += [