Steam Deck

Control+Alt+5 while in big picture mode will give you a command shell.

username: deck
password: (?)

Hold [...] button (the one with three dots on the front of the deck) and while holding it, press and hold POWER button, wait for the sound, release ONLY the POWER button until the menu appears and release [...] to boot into

Troubleshooting

Steam Deck Black Screen After switching to desktop

aka: Steam deck blackscreen switching to desktop

USB Keyboard required.

1. Go to the command shell (instructions on this page) and login.
2. rm -rf ~/.local/share/kscreen/*
3. CTL-ALT-F1 to go back to Big Picture Mode and then try to switch to desktop.