Stucked in recovery mode while installing with UBports Installer

[MrT10001]

@shadowcastiel Try:

fastboot oem unlock

and:

fastboot oem unlock_critical

[ShadowCastiel]

@mrt10001 for both commands the following output:

fastboot oem unlock_critical
FAILED (remote: '	Device already : unlocked!')
fastboot: error: Command failed

[MrT10001]

@shadowcastiel Great so that means the device is definitely unlocked.

Flash the device back to the required stock ROM and go into developer options and ensure that the check for OEM unlock is in the unlock position (it may be giving you a false flag).

When you have done that, install TWRP and ensure all the partitions are on EXT4.

[ShadowCastiel]

@mrt10001 how can I flash it back to stock rom? I am not able to find a device:

adb reboot bootloader
error: no devices/emulators found

Is my phone now bricked? What happened here? How can I install TWRP now? I am really not sure for now.

[MrT10001]

@shadowcastiel make sure the phone is disconnected from the USB cable and switch the phone off. Wait a few seconds to make sure. Then press the power button till and volume down buttons together until the phone switches on. This will boot you into fastboot mode. Connect the phone to the PC and install TWRP using the fastboot command:

fastboot flash recovery <location and name of your TWRP img file>

Once TWRP is installed, your phone should be picked up by the PC and you can copy the stock ROM image over to the root of your device and side load it with TWRP.

Download the stock image from here

I used rollback image.

Once the image is installed, reboot the device and set Android up. Make sure it is on Android 9 and enable developer options. Make sure OEM unlock is enabled or has been enabled.

Then reboot the phone to the bootloader, install TWRP and ensure the data and storage partitions are EXT4 - this is important as UT won't install.

Try UT install again. If it fails, go back to TWRP (you will have to install it again) and wipe the data partition and ensure the data and system partitions are EXT 4, then wipe all the partitions except OTG. If you get warnings when these processes are happening, when they end reboot to fastboot, install TWRP and do it again.

If no warnings try the UT install again.

I apologise, I have skimmed over a bit.

[Lakotaubp]

@mrt10001 Just out of interest could you not just install TWRP then wipe and format EXT4 system,data and cache as needed like with the OP5 then run the installer.

Edit: If on Android 9 that is.

[MrT10001]

@lakotaubp If it was on Android 9, but I would go back to stock to a)make sure it is on Android 9 and b) to ensure the OEM unlock button has been checked.

It is a faff, but I have found with all the devices, if an error get thrown up, back tracking and going back to stock is the best way to success.

[Lakotaubp]

@mrt10001 Good point best to check that everything is as it should be to avoid false errors and know the process is correct.

[ShadowCastiel]

@lakotaubp is now all fine with the OnePlus 6. I recovered it with the Qualcomm Emergency Downloader.

[Lakotaubp]

@shadowcastiel Good to know. Could you please mark as solved https://forums.ubports.com/topic/6311/how-to-ask-a-question-and-then-mark-it-as-solved Thanks