diff --git a/Marlin/Marlin_main.cpp b/Marlin/Marlin_main.cpp
index 10d26ac98bd9143cf8cbd50a79f4933882c2cd50..99786e61701c49c1f6e09ccce72d53f4ff225115 100644
--- a/Marlin/Marlin_main.cpp
+++ b/Marlin/Marlin_main.cpp
@@ -5038,7 +5038,7 @@ inline void gcode_M121() { endstops.enable_globally(false); }
    */
   inline void gcode_M156() {
     uint8_t addr = code_seen('A') ? code_value_short() : 0;
-    int bytes    = code_seen('B') ? code_value_short() : 0;
+    int bytes    = code_seen('B') ? code_value_short() : 1;
 
     if (addr && bytes > 0 && bytes <= 32) {
       i2c.address(addr);