Bad screen resolution permanently crashes Poco F1 In short: I used SecondScreen app and changed the screen resolution to a bad one. The app autostarts and changes my resolution automatically. This causes a boot loop. What can I do?
In detail:
This is what I did on my non-rooted Poco F1:

installed Second Screen
I gave it the permissions it needed, using ADB via my PC, and other permissions it asked via UI .
I chose some big resolution.
I shut down the PC, before disconnecting the phone from PC.
The phone was stuck in the weird resolution, so I restarted it.
it is now in an infinite boot loop. :(

It starts booting normally, but than the screen resolution becomes bad (see the photo), and, before finishing the booting, it restarts again :(
At last, the recovery menu is reached and it gives me 3 options.

Reboot (this is the restarting loop that brings me back to the same menu)
Access via MI PC Suite: I cannot access the device this way; the device is not detected. It never sees the device, except in Fastboot it says: &quot;Try connect in normal mode first then switch&quot;, but I cannot enter &quot;normal&quot; mode.
Wipe the data (if at all possible, I would prefer to avoid losing the data).

What I know:
Codename:       beryllium
Bootloader:     locked
Anti version:       1

I can get my phone into FASTBOOT and adb sideload modes, but unfortunately not in the &quot;normal&quot; adb mode. Can I uninstall the app somehow, stop it from autostart, undo its damage, or anything to fix the phone without losing the data?
A non boot-loop fix was done by typing:
From adb shell, type:
wm size reset
wm density reset

but I cannot find out how to do that from FASTBOOT or sideload....
I fixed it* by letting the phone bootloop until fully discharged. I then plugged the phone into the computer and turned the phone on as soon as it charged enough to allow me this. At that point there is a brief window where full ADB access is possible, but only because I did have USB debugging enabled after all, but the bootloop was too fast to allow full ADB access at any point.
I imagine the phone does a fuller/slower reset when discharged. At one point in the &quot;good&quot; bootloop it shows a nice, round, &quot;loading&quot; circle, and that is when I got ADB access. There is little time before &quot;bad&quot; bootloop is resumed.

This is what I kept entering in command line during the &quot;loading&quot; circle boot phase, until it finally indicated that I have the full ADB access by showing the alphanumeric ID of the phone and &quot;device&quot; after it:
adb devices



List of devices attached
    03464364da54  device


Uninstall the culprit app called SecondScreen, by first finding its proper name, and then uninstalling it via adb:
adb shell pm list packages | grep second 

pm uninstall -k --user 0 nameOfTheAppReturnedByTheAboveCommand 


This was not enough, and the phone entered the &quot;bad&quot; bootloop again, so I discharged it again and reset the screen size and density (DPI I believe):
adb shell wm size reset

adb shell wm density reset



It works like new now.