--- a/xpcom/build/nsWindowsDllInterceptor.h
+++ b/xpcom/build/nsWindowsDllInterceptor.h
@@ -1177,16 +1177,19 @@ protected:
           // jmp absolute indirect m32
           foundJmp = true;
           int32_t offset = *(reinterpret_cast<int32_t*>(origBytes + nOrigBytes + 2));
           int64_t* ptrToJmpDest = reinterpret_cast<int64_t*>(origBytes + nOrigBytes + 6 + offset);
           intptr_t jmpDest = static_cast<intptr_t>(*ptrToJmpDest);
           JumpPatch jump(nTrampBytes, jmpDest, JumpType::Jmp);
           nTrampBytes = jump.GenerateJump(tramp);
           nOrigBytes += 6;
+        } else if ((origBytes[nOrigBytes + 1] & (kMaskMod|kMaskReg)) == BuildModRmByte(kModReg, 2, 0)) {
+          // CALL reg (ff nn)
+          COPY_CODES(2);
         } else {
           MOZ_ASSERT_UNREACHABLE("Unrecognized opcode sequence");
           return;
         }
       } else {
         MOZ_ASSERT_UNREACHABLE("Unrecognized opcode sequence");
         return;
       }