I tried installing it on one of my existing Raspberry Pi 3s that I have at home (specifically Raspian w/ RetroPie), the AIO package doesn’t seem to finish properly before rebooting on its own. I’d like to start from scratch on a clean RPi&SD card, but I would like to clean off any of the HA stuff on this existing RPi.
All the files should be under /srv/homeassistant and /home/homeassistant/.homeassistant. If you delete both of those directory structures that’ll remove everything other than binary packages that were installed.