At least on Android, when my Samsung Galaxy Note (I loved that phone - replaceable battery, pressure sensitive stylus, IR blaster, OLED, audio jack, water resistant - they went downhill from there IMO) finally end of lifed, I just used the official Samsung tool to upload a community image on it. The process wasn't horrendously difficult. I don't know if people would do it, but it was a clear set of steps that even a tech novice could accomplish if following carefully.