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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?

Thanks :)

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I'm sorry. but I believe that it is a hardware issue. The touch feedback and the capactive key feedback is sometimes carried over by the same flex ribbon. So, it could be either a loose connection of the flex cable and/or a broken flex cable or some other type of hardware issue with the touchscreen.

The fingerprint should use a separate connection and it definitely does as it is on the back. So, it could also be something wrong with the motherboard.

I do not see a software issue here. Also, with all that you have tried, I do not see much that you are left with. The best idea would be to bring the device to a Xiaomi service center. I hope you live in a location where it is officially sold and you have warranty coverage.

  • Thanks for your help! Sadly, I imported the phone from China to UK, so there aren't any official service centres here, and it has no warranty anyway (even if it did it would definitely be voided by now!) :'( It seems strange to be a hardware issue, since the touchscreen and fingerprint scanner died simultaneously. If it is a hardware issue, it must surely be the motherboard? – Luke May 9 '18 at 14:16
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    Yes, I believe that it is the motherboard. Because touchscreen and fingerprint are connected via different connectors and they would usually not die together. In your case I'd recommend you to bring it to a local repair shop (if you have one around). And the technician should be able to identify where the issue is. You can then import that particular hardware part from China and have your phone fixed. – singhnsk May 10 '18 at 4:47

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