My wife’s PiboyDMG stopped working and wouldn’t boot. After some investigation it was due to the SD card being fried (no surprise there, SD cards are horribly unreliable) so I tried setting it up to boot from a 128GB mini usb drive. I followed the same steps I would have with an sd drive:

1. Dowload retropie
2. Install retropie on the usb drive using balena etcher
3. Download the Piboy DMG firmware updates ,copy the Piboy DMG files to the usb drive and update the config file
4. Boot up 🙂