A week ago all the input sensors (touch screen, capacitive buttons, fingerprint scanner) on my Xiaomi Mi A1 died, completely out of the blue. The device had never been rooted, and was running the stock ROM (Android One, Android 8).
I tried a factory reset, but nothing changed. I then tried re-flashing the stock ROM with MiFlash and TWRP. I ended up bricking it, but revived it by deepflashing - I shorted the test points to put it into EDL mode, and reflashed the stock ROM with MiFlash. This worked, but was stuck in a bootloop, where the booting animation would hang forever. I tried flashing a custom PixelExperience ROM, with a clean stock ROM and wiped partitions, but it also hung on the boot animation.
I eventually fixed this by flashing the persist partition in EDL mode (I knew this would destroy my IMEI, but I was out of options).
Now the device boots successfully, and I can use it with an OTG mouse with both stock and PixelExperience ROMs.
However, the original problem persists. The input sensors still don't work at all - there is no feedback from any touch. In addition, it can't connect to any mobile network (IMEI = 0). It can find WiFi networks, but not connect to them. It also appears to occasionally do random touch events on the screen.
At this point I am very much out of ideas - does anyone have any ideas of what might be the issue, and any suggestions of what I could try next?