TWRP 18.104.22.168 release introduced multiuser decryption which means no more error 255 or other multiuser backup errors on devices with multiple users setup. The problem is, TWRP requires all the users to be decrypted in order for the backup to be successful. But, I can't seem to decrypt Island / Work profile user (user 11) and Parallel apps user (user 999) in my OnePlus 6 running Android 10.
Note: Parallel apps user is specific to OnePlus devices.
Here's what happens when I enter my PIN in TWRP on boot or through command-line:
Attempting to decrypt data partition or user data via command line. Attempting to decrypt FBE for user 0... User 0 Decrypted Successfully Attempting to decrypt FBE for user 10... Failed to decrypt user 10 Attempting to decrypt FBE for user 11... Failed to decrypt user 11 Attempting to decrypt FBE for user 999... Failed to decrypt user 999 Data successfully decrypted Updating partition details... ...done
I can explicitly decrypt secondary user 10, so no problem there, but I am unable to do that for Work Profile / Island user and Parallel Apps user (user 999).
twrp decrypt MY_PIN_FOR_USER_0 999 doesn't work. Running
locksettings verify --user 11 and
locksettings verify --user 11 gives me
Profile uses unified challenge
So, how do I decrypt these user accounts so that I can make TWRP backups?
I am unable to put the answer to this question to my use. What is a "synthetic password" and how is it used by Android?
Edit: From the TWRP issue tracking link shared by alexcs, the solution for work profile is to separate its lockscreen credentials from the primary/main user. This seems to work so far. However, it doesn't not work for decrypting parallel apps user (999).