I had a Volla and UBtouch corr: SFOS with Waydroid worked very fine. But unfortunately, a few months ago, the device broke for unknown reasons after a 1 hour Jitsi conversation with a friend, maybe because of overheated CPU? Device crashed and it’s not possible to boot or reflash it anymore. It seems to be dead now. Maybe somebody knows the right pads on PCB to connect with a tweezer for reset? Disconnecting the battery didn’t help.