diff --git a/.github/workflows/wp24b2-inplace-gc.yml b/.github/workflows/wp24b2-inplace-gc.yml
index 3b4605a..9e1d1dc 100644
--- a/.github/workflows/wp24b2-inplace-gc.yml
+++ b/.github/workflows/wp24b2-inplace-gc.yml
@@ -62,22 +62,33 @@ jobs:
               if not re.search(pattern, asm, re.S):
                   raise SystemExit(f"ABI validation failed: {label}")
 
-          # Detour callbacks: L must arrive in ECX on WoW 5875 x86.
-          m = re.search(r"mov\s+edx,\s*0x6f7340.{0,240}?push\s+0x([0-9a-f]+)", asm, re.S)
-          if not m:
-              raise SystemExit("ABI validation failed: collector callback address not found")
-          cb = m.group(1).lstrip("0") or "0"
-          pos = asm.find(cb + ":")
-          if pos < 0 or not re.search(r"mov\s+esi,\s*ecx", asm[pos:pos+800]):
+          def callback_snippet(target, window):
+              m = re.search(rf"mov\s+edx,\s*0x{target}.{{0,240}}?push\s+0x([0-9a-f]+)", asm, re.S)
+              if not m:
+                  raise SystemExit(f"ABI validation failed: callback for 0x{target} not found")
+              cb = m.group(1).lstrip("0") or "0"
+              pos = asm.find(cb + ":")
+              if pos < 0:
+                  raise SystemExit(f"ABI validation failed: callback body {cb} not found")
+              return asm[pos:pos+window]
+
+          # Collector callback: same proven B1 code shape, L copied from ECX.
+          collector = callback_snippet("6f7340", 900)
+          if not re.search(r"mov\s+esi,\s*ecx", collector):
               raise SystemExit("ABI validation failed: collector callback does not consume L from ECX")
 
-          m = re.search(r"mov\s+edx,\s*0x6f6ef0.{0,240}?push\s+0x([0-9a-f]+)", asm, re.S)
-          if not m:
-              raise SystemExit("ABI validation failed: lua_close callback address not found")
-          cb = m.group(1).lstrip("0") or "0"
-          pos = asm.find(cb + ":")
-          if pos < 0 or not re.search(r"mov\s+esi,\s*ecx", asm[pos:pos+600]):
-              raise SystemExit("ABI validation failed: lua_close callback does not consume L from ECX")
+          # lua_close is much smaller in B2 because fragment reconstruction is gone.
+          # Zig may preserve ECX in any callee-saved register or a stack slot; do
+          # not require the B1-specific ESI allocation.
+          close = callback_snippet("6f6ef0", 800)
+          ecx_preserved = re.search(
+              r"(?:mov\s+(?:esi|edi|ebx|ebp|eax|edx),\s*ecx|push\s+ecx|mov\s+(?:dword ptr\s*)?\[[^\]]+\],\s*ecx)",
+              close,
+          )
+          if not ecx_preserved:
+              print("lua_close callback snippet:")
+              print(close)
+              raise SystemExit("ABI validation failed: lua_close callback does not preserve L from ECX")
 
           # Native helper ABI observed directly in WoW 5875:
           # lua_gc_remove_objects: ECX=L, EDX=&list, stack arg all=0.
@@ -89,10 +100,9 @@ jobs:
               "rootudata lua_gc_remove_objects ABI",
           )
 
-          # B2 also calls lua_gc_remove_objects through a runtime link address;
-          # require at least one call site with ECX loaded from L and EDX nonzero.
+          # At least one dynamic-list remove call must load L into ECX.
           require(
-              r"mov\s+eax,\s*0x6f7210.{0,220}?mov\s+ecx,\s*e[a-z]{2}.{0,180}?call\s+eax",
+              r"mov\s+eax,\s*0x6f7210.{0,240}?mov\s+ecx,\s*e[a-z]{2}.{0,200}?call\s+eax",
               "chunk lua_gc_remove_objects fastcall callsite",
           )
 
@@ -118,6 +128,7 @@ jobs:
 
           sha256sum "$DLL" | tee SHA256SUMS.txt
       - uses: actions/upload-artifact@v4
+        if: always()
         with:
           name: WeirdPerformance-2.4-B2-GC-InPlace-Safe-Sweep
           path: |
@@ -125,4 +136,4 @@ jobs:
             experiments/wp24b-gc/SHA256SUMS.txt
             experiments/wp24b-gc/BINARY_INFO.txt
             experiments/wp24b-gc/ABI_DISASM.txt
-          if-no-files-found: error
+          if-no-files-found: warn