[Redmi K20 Pro / Xiaomi Mi 9T Pro Questions & Answe] LyNChP1N:
I had the 5 point touch screen replacement on my phone and it had fingerprint sensor issues and random ghost touch issues.

It is a myth that these issues cannot be solved on 5 point touch displays.

1. Over time what is found is that disabling 'three finger swipe' screenshot gesture in settings gets rid of ghost touches. 100% gone. I can type without typos now. Just search screenshot gesture in miui settings.

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2. The fingerprint issue is solved on repeated attempts at recalibration. What i did was remove all registered fingerprints. Then i did calibration with an A4 white paper folded in half and a black paper while in a relatively dark room(no lights on,natural light). i got a pass on the performance test. keep trying until you get a pass and fingerprint will work perfectly. I tried to keep 3/4th of display covered by a4 and black paper and pressing the fingerprint sensor over the white and black paper respectively to ensure coverage.(also try increasing display brightness to 25%/50% and full brightness. I got pass while at aboot 25% - 50% brightness)

Additionally, I have read in another post that if you add same finger in 4 orientations(up,down,left,right-change orientation when you add next fingerprint using same finger), it will work faster. I havent tested it out, check it out as well. Couldnt find that post again. All these solutions are from relentless scouring of the internet.

3. Try velis auto brightness app if your screen becomes too dark in low lit environments. A way to edit default auto brightness values to be higher in dim environments would have been the perfect solution

This is working on stock miui 12 and xiaomi.eu roms and with 5 point touch displays(have replaced multiple types)

4. If you really need widevine L1 to be fixed, you wil need to use xiaomi.eu 12.5.5 or 12.5.6. Find those roms on xiaomi.eu website. These roms will fix widevine L1 no matter how you lost it.

Evolution X rom based on android 11 seems to have widevine L1 support but I am not sure.

The best thing to do is to flash fastboot rom of miui 10.3.5 based on android 9. Everything works perfectly, no rom has this level of fingerprint function(not even stock mui11or 12) or display brightness. The display brightness issue is fully gone on this rom. If you wish to upgrade to another rom, flash it after fastboot flashing stock miui 10.3.5. It preserves the calibraiton data for the hardware.(Without doing this, I was facing high battery drain, bluetooth quality issues, call quality issues, slow fingerprint sensor, dim display in lowlight environments) I still recommend above steps 1and 2 even if you are on miui 10.3.5

I have added a few useful posts by other members if you dont know how to do any of the above mentioned steps.

1. Simple guide to flashing on K20 Pro

His advice on not using orangefox for custom roms other than xiaomi.eu roms may be right, I have not tried it. Orangefox personally works best for me.

2. Guide to flashing custom roms, changing between miui and custom roms

Instructions are good except that you can do fastboot install and switch from stock miui to xiaomi.eu without formatting internal storage. Follow below

Spoiler content hidden.

3. Bootloader unlock, twrp, root instructions and rom links

4. My guide to pass safetynet, hide root access on any rom working upto February 2023