diff --git a/py/bc.c b/py/bc.c
index 0d0a0b12f9..e5abea2440 100644
--- a/py/bc.c
+++ b/py/bc.c
@@ -308,8 +308,8 @@ STATIC const byte opcode_format_table[64] = {
     OC4(B, B, O, U), // 0x44-0x47
     OC4(U, U, U, U), // 0x48-0x4b
     OC4(U, U, U, U), // 0x4c-0x4f
-    OC4(V, V, V, V), // 0x50-0x53
-    OC4(B, V, V, V), // 0x54-0x57
+    OC4(V, V, U, V), // 0x50-0x53
+    OC4(B, U, V, V), // 0x54-0x57
     OC4(V, V, V, B), // 0x58-0x5b
     OC4(B, B, B, U), // 0x5c-0x5f
     OC4(V, V, V, V), // 0x60-0x63
diff --git a/tools/mpy-tool.py b/tools/mpy-tool.py
index bc8ac4fbd3..2bb9fc367e 100755
--- a/tools/mpy-tool.py
+++ b/tools/mpy-tool.py
@@ -107,8 +107,8 @@ def make_opcode_format():
     OC4(B, B, O, U), # 0x44-0x47
     OC4(U, U, U, U), # 0x48-0x4b
     OC4(U, U, U, U), # 0x4c-0x4f
-    OC4(V, V, V, V), # 0x50-0x53
-    OC4(B, V, V, V), # 0x54-0x57
+    OC4(V, V, U, V), # 0x50-0x53
+    OC4(B, U, V, V), # 0x54-0x57
     OC4(V, V, V, B), # 0x58-0x5b
     OC4(B, B, B, U), # 0x5c-0x5f
     OC4(V, V, V, V), # 0x60-0x63