Emergency Reset. No App Required

If your keyboard ever gets into an unexpected state, you can restore all keys to their factory defaults directly from the keyboard without needing this app or a computer. Hold Fn + J + Z for 4 seconds. On a keyboard with two Fn keys, if one does not work, try the other.

The backlight flashes briefly to confirm the reset. To check without seeing it, press a key you had remapped: it does its normal job again. Or, in this app, Review Changes on This Keyboard lists no changed keys.