[Redmi K20 Pro / Xiaomi Mi 9T Pro Guides, News, & D] maddy143ded:
In my aim to bypass the Google Photos storage limitation I tried my hand at (21-05-2021)Pixel Experience Rom (O.S.S Based). I was a painless experience to Flash the rom file through Orange Fox recovery. Initially the Rom was super stable and had everything I would use for my Daily Driver. Soon after I finalised everything in the Rom I received the 26-05 update of the Rom. I of course installed it as advised in the thread. Soon after rebooting everything was going fine when I received a WhatsApp video call, but front Cam kept going up and down with great difficulty. I tried the default camera app of the Rom to check and there too front cam would not Pop out smoothly and I would get error for Calibrating the Front cam. On going for calibration it would not work. I tried doing a complete clean flash of the 26-05 Rom but error would not go away.

Now I got worried and tried to do a Clean flash of Stock 12.0.5 Miui Indian Rom via Recovery but the Front cam was less then stable. It would work sometimes and some times it would pop up a little less the full out. Due to that the Cam pic would come slightly blurry. I Googled the front cam calibrating issue and found a lot of references to Persist partition. Also guys @Pixel experience telegram channel guided me through a lot of trial and error but nothing worked. I tried restoring an 2 months old FOX backup of then Stock Miui installation. That seemed to help a little but cam was still Unstable. I tired to Do a Clean Fastboot Flash of the 12.0.5 Miui stock and that to gave similar unstable results where I would be required to calibrate the front cam which would not work.

Then following some YouTube instructions i decided to try the dreaded Persist image flash(from the Fastboot stock Image). At this moment I was resigned to loose my Widewine L1.... But that too did not help a bit and A repeat Clan Fastboot flash of Stock also failed to do anything to the Front cam problem. Finally I gave up the whole thing and decided to just use the phone without Selfies cam.

Did everything needed to get a working Phone with stock Miui rooted and everything. But now the phone kept getting Encrypted despite doing everything to prevent that. (DM verity and also Ofox force disable encryption).

Finally tiring of all the crap, I went to sleep leaving my phone as it was. In the morning while searching for a solution I cam across a Orange fox Backup I had taken a while back which had only the most Important Partitions (Persist, VBMeta, etc) on my computer. I said lets try this one too..

I did a clean Fastboot flash of current stock Miui and then flashed latest Ofox recovery via ADB. Then in recovery (where i again faced the encryption issue which i this time chose to do a flash unlock.)

In recovery I did a complete wipe and format of data partition. After this I copied my Fox backup and Rom Folder from the computer.

I restored the small Backup (It has Persist, Vbmeta, Dtbo etc) After this without wiping anything I flashed Stock recovery 12.0.5 Miui (an older downloaded copy from my computer). Flashed DM -verity file. and after wiping dalvic rebooted the system. Took a while but System booted up fine. After this I started the process of restoring the Google Backup. After a couple of reboots and finishing the setup I tried the front cam . It worked smoothly for all the 20 or so times i tried it. SO finally i was able to get rid of the Problem..

Though I do seem to have lost the Widewine L1... So if anyone has a sureshot way to get that back please help me out..

So lesson I learned is Always have Complete Backup and special Backup of important Partitions....