[OnePlus 9 Pro] Releece:
Hey all,

I hope it's ok for me to post in this thread, I'm new here. Any knowledge I might gain, I will give back x times more !

In my device forum there is only a thread for TWRP 3.6.0 and it's pretty much dead since a year ago... I made a post there but now rewriting it a bit for posting here.

I have a OnePlus Nord 2 5G (DN2103, "denniz") running TWRP 3.7.0 built for my device (twrp-3.7.0_11-0-denniz.img) and I just flashed the newest EvolutionX ROM (Android 13, February sec. patch) also for denniz, coming from OxygenOS (11.A.21). Ofc bootloader is unlocked and vbmeta was flashed. This is NOT an a/b partitioned device.

I'm not able to decrypt /data/media/ and not sure what to try to fix it / or if I should leave it like this. So here goes what happened:

I succesfully flashed TWRP 3.7.0 on DN2103_11_A.21 using fastboot. After rooting OOS, all good & TWRP persists as recovery (stock stops overwriting TWRP).

I decided to install EvolutionX ROM, because there is no fastboot / custom recovery / root options for OOS Android 12 versions with my device (yes very f'ed up from OP).

Before installing, the ROM instructions were to format DATA (wipe > format DATA > type "yes"). I remember seeing a red line "unable to decrypt FBE partition" in the log, but didn't know what that meant at the time (file-based encryption), and for the rest it reported "operation completed succesfully".

After this, the media folder (at /data/media) was removed completely....

When I went to mount, it didn't show internal storage as 0 bytes as it does with most people that have decryption problems, but reported the normal size of my storage. Except in Windows, using MTP, I could open my device but copying a file / creating new folder was all not possible, neither was Windows able to show free / total size of internal storage. I understand now this must be because /data/media is normally where internal storage is mounted to /sdcard/ and is made available over MTP.

Then using TWRP file explorer I could succesfully open the /data/ folder, but it was empty! (except for some 1kB file) So strangely it seems it did actually not simply FORMAT DATA, but it DELETED it. I do remember after completing the data format, a prompt came up and said something along the lines of "... you might need to repopopulate the /data/media/ folder by booting to system ..." Unfortunately I don't remember exactly, but it was a single sentence.

I SOLVED the problem of not being able to transfer the ROM.zip using MTP, by transfering it using ADB push command to /data/ and flashing my ROM went without any error whatsoever. System runs smooooth as butter.

So now I was going to root with Magisk. But if I go into TWRP now, it can't decrypt my /media/data folder (USERDATA), saying wrong password. I tried everything, no screen lock, pin, password...

Now I'm not sure how to continue. Do I push anything I might need to flash in the future over ADB into non USERDATA folders, then flash and delete? Is there any downside to keeping it in this state apart from inconveniece when flashing or would that be OK?

I don't know if Magisk or TWRP need acces to /data/media/ to work correctly? Can you tell TWRP to save backups to another location? (I use SwiftBackup anyway so not a big problem)

Ofcourse I'd rather fix this, but searching DuckDuckGo this error gives me many hits and everyone says to go about it another way. Some guides go all the way into editing FSTAB files manually. Then flashing back stock ROM, factory resetting with stock recovery, boot system, then flash TWRP, flash ROM, flash Magisk...

A few guides say you need to flash the no-verity-opt-encrypt.zip, reboot into TWRP and this would fix it. But isn't that outdated and incompatible for devices with a vbmeta.img, or could it still help?

It's my daily driver so I miss my (communication) apps and want to discover the new Android 13 & Evolution! I'm not restoring my data yet, else all that time spent configuring everything will be for nothing if I might have to back it up Again and then format everything...

Any comment at all would be greatly appreciated!

EDIT: Maybe I should try flashing TWRP 3.6.0 or 3.5.x first, see if that works? Can I safely flash an older version of TWRP with the current version? (I'm running 3.7.0)

EDIT2: Wait... Is the TWRP for denniz 3.7.0 made for A11 and the build in this thread for A12/13? A bit confused because they have the same versioning. So I would just need to flash this build or wait till the one for my device gets updated? I have no idea how device specific TWRP is; the Nord 2 has a mediatek chip, could this run on the kernel of this build?