Move fake EE_HANDS (#18352)

quantum/eeconfig.c

@@ -57,16 +57,6 @@ void eeconfig_init_quantum(void) {
     eeprom_update_dword(EECONFIG_RGB_MATRIX, 0);
     eeprom_update_word(EECONFIG_RGB_MATRIX_EXTENDED, 0);
 
-    // TODO: Remove once ARM has a way to configure EECONFIG_HANDEDNESS
-    //        within the emulated eeprom via dfu-util or another tool
-#if defined INIT_EE_HANDS_LEFT
-#    pragma message "Faking EE_HANDS for left hand"
-    eeprom_update_byte(EECONFIG_HANDEDNESS, 1);
-#elif defined INIT_EE_HANDS_RIGHT
-#    pragma message "Faking EE_HANDS for right hand"
-    eeprom_update_byte(EECONFIG_HANDEDNESS, 0);
-#endif
-
 #if defined(HAPTIC_ENABLE)
     haptic_reset();
 #else

quantum/split_common/split_util.c

@@ -139,6 +139,20 @@ void split_pre_init(void) {
     if (!eeconfig_is_enabled()) {
         eeconfig_init();
     }
+    // TODO: Remove once ARM has a way to configure EECONFIG_HANDEDNESS within the emulated eeprom via dfu-util or another tool
+#    if defined(INIT_EE_HANDS_LEFT) || defined(INIT_EE_HANDS_RIGHT)
+#        if defined(INIT_EE_HANDS_LEFT)
+#            pragma message "Faking EE_HANDS for left hand"
+    const bool should_be_left = true;
+#        else
+#            pragma message "Faking EE_HANDS for right hand"
+    const bool should_be_left = false;
+#        endif
+    bool       is_left        = eeconfig_read_handedness();
+    if (is_left != should_be_left) {
+        eeconfig_update_handedness(should_be_left);
+    }
+#    endif // defined(INIT_EE_HANDS_LEFT) || defined(INIT_EE_HANDS_RIGHT)
 #endif
     isLeftHand = is_keyboard_left();