Cheat Sheet: 10-speed and 11-speed crash mode
To reset crash mode on 10-speed (6770) and 11-speed Di2 (6870, 9070, R8050, R9150, GRX), you press and hold the button on your junction box for 5 seconds until a red light flashes.
The rear derailleur will now reset and go through all the gears, so make sure sure you spin the cranks until it’s done.
Once it has gone through all the gears you’re done and ready to get back to enjoying your ride.