diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index cdc0a785c6d72e..70b6bb940841ac 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -2935,9 +2935,10 @@ dummy_func(
         };
 
         tier1 op(_SPECIALIZE_JUMP_BACKWARD, (--)) {
-        #if ENABLE_SPECIALIZATION
+        #if ENABLE_SPECIALIZATION_FT
             if (this_instr->op.code == JUMP_BACKWARD) {
-                this_instr->op.code = tstate->interp->jit ? JUMP_BACKWARD_JIT : JUMP_BACKWARD_NO_JIT;
+                uint8_t desired = tstate->interp->jit ? JUMP_BACKWARD_JIT : JUMP_BACKWARD_NO_JIT;
+                FT_ATOMIC_STORE_UINT8_RELAXED(this_instr->op.code, desired);
                 // Need to re-dispatch so the warmup counter isn't off by one:
                 next_instr = this_instr;
                 DISPATCH_SAME_OPARG();
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index b83ab941ed2b70..eada299315034e 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -7711,9 +7711,10 @@
             /* Skip 1 cache entry */
             // _SPECIALIZE_JUMP_BACKWARD
             {
-                #if ENABLE_SPECIALIZATION
+                #if ENABLE_SPECIALIZATION_FT
                 if (this_instr->op.code == JUMP_BACKWARD) {
-                    this_instr->op.code = tstate->interp->jit ? JUMP_BACKWARD_JIT : JUMP_BACKWARD_NO_JIT;
+                    uint8_t desired = tstate->interp->jit ? JUMP_BACKWARD_JIT : JUMP_BACKWARD_NO_JIT;
+                    FT_ATOMIC_STORE_UINT8_RELAXED(this_instr->op.code, desired);
                     next_instr = this_instr;
                     DISPATCH_SAME_OPARG();
                 }