[OnePlus 6T  Guides, News, & Discussion] Lartsch:
This thread should be deleted.

Hello together,

as I wanted to see if I get F2FS and decryption running, I want to share my progress and exchange with others.

I got both working but there are a few issues once the system is running, at least if decrypted. When encrypted, everything seems running nice on f2fs.

Here's what I did:

ENABLE F2FS AND DISABLE ENCRYPTION (IF NEEDED)

1.	Flash full fastboot rom to make sure everything is clean

2.	Boot to stock recovery and wipe /data so it gets cleanly formatted as ext4 (not really needed)

3.	Boot and install TWRP (blu_spark) and reformat /data as f2fs

I chose latest blu_spark recovery as I think it's more stable and I don't need recovery decryption for this matter

4.	Reboot to recovery

5.	Flash custom kernel with f2fs support or keep stock

blu_spark didn't work for me for some reason but Smurfkernel and ElementalX were fine, also

STOCK KERNEL SUPPORTS F2FS BY NOW

6.	Flash the universal dm-verity and forceencryption remover by zackptg5 found here

Only if you really need it!

NOT RECOMMENDED AND NOT NEEDED FOR HAVING F2FS WORK

7.	Flash Magisk v18.0

8.	Reboot

9. Profit (or not)

Even if hard to believe with the already amazing speeds of the OP6/T, I think I could feel a little improvement in boot time and app opening times.

Update: I wouldn't recommend doing this as of now to anyone. Maybe results with an AOSP based rom are better (please try and report), but using OxygenOS in combination with currently available kernels, the system turns out unstable and is not usable reliably. There are different weird glitches etc. Do this on your own resposibility and please share if you make any progress making OOS and/or AOSP run stable (recovery versions, file patches, kernels, settings, etc). I'm not an Android developer myself.

ENCOUNTERED ISSUES

1.	Can't use any unlock method. Deleting gatekeeper and locksetting files through TWRP works but setting a new PIN results in not being able to unlock again. The PIN is entered correctly but still it reports "wrong password". But actually it detects that the PIN is correct since it doesn't trigger a lockout time. Logcat occurences can be found below.

FIXED BY NOT DECRYPTING DATA (?)

2.	On first boot there will be some app crashs and lags. They settle after a few minutes and one or two reboots.

ALSO FIXED BY NOT DECRYPTING DATA (?)

3.	One time I had to reflash Magisk after the first boot

UNLOCK BUG LOGCAT OCCURENCES - HELP NEEDED!

Here are some logcat lines which I think are related to the unlock bug.

E GatekeeperHalDevice: verify
E GatekeeperHalDevice: ret: 0
E GatekeeperHalDevice: resp->status: -24

E GatekeeperHalDevice: verify
E GatekeeperHalDevice: ret: 0
E GatekeeperHalDevice: resp->status: -30

I LockSettingsService: Device doesn't implement AuthSecret HAL
E LockSettingsStorage: Cannot read file java.io.FileNotFoundException: /data/system/gatekeeper.password.key: open failed: ENOENT (No such file or directory)
E LockSettingsStorage: Cannot read file java.io.FileNotFoundException: /data/system/password.key: open failed: ENOENT (No such file or directory)
E LockSettingsStorage: Cannot read file java.io.FileNotFoundException: /data/system/gatekeeper.pattern.key: open failed: ENOENT (No such file or directory)
E LockSettingsStorage: Cannot read file java.io.FileNotFoundException: /data/system/gatekeeper.gesture.key: open failed: ENOENT (No such file or directory)
E LockSettingsStorage: Cannot read file java.io.FileNotFoundException: /data/system/gesture.key: open failed: ENOENT (No such file or directory)

E keystore: Changing user 0's password while locked, clearing old encryption

E JavaBinder: *** Uncaught remote exception! (Exceptions are not yet supported across processes.)
E JavaBinder: java.lang.RuntimeException: android.os.RemoteException: Non-OK response verifying a credential we just set: -1
E JavaBinder:	at android.os.Parcel.writeException(Parcel.java:1779)
E JavaBinder:	at android.os.Binder.execTransact(Binder.java:765)
E JavaBinder: Caused by: android.os.RemoteException: Non-OK response verifying a credential we just set: -1
E JavaBinder:	at com.android.server.locksettings.LockSettingsService.setUserKeyProtection(LockSettingsService.java:1602)
E JavaBinder:	at com.android.server.locksettings.LockSettingsService.setLockCredentialInternal(LockSettingsService.java:1483)
E JavaBinder:	at com.android.server.locksettings.LockSettingsService.setLockCredential(LockSettingsService.java:1397)
E JavaBinder:	at com.android.internal.widget.ILockSettings$Stub.onTransact(ILockSettings.java:141)
E JavaBinder:	at android.os.Binder.execTransact(Binder.java:752)