Unrooting/Returning to stock

Caution

These instructions were written for and have only been tested on phoenix devices (PICO 4, PICO 4 Pro and PICO 4 Enterprise). They likely will not work on sparrow devices (PICO 4 Ultra or Ultra Enterprise). If you try anyway, here be dragons!

Danger

Locking the bootloader, like unlocking it, requires your headset to be factory reset! You will lose anything you do not back up!

Before you begin

1. Ensure you have the files output by picounlock to the device_backup folder (or your own dump of abl.bin and optionally devinfo.bin), as well as your unlock key.
2. Connect your headset to your computer via a reliable USB-C cable.
3. You will also need a copy of adb and fastboot. If these are not installed on your computer, they are included with picounlock.

Steps

1. adb reboot bootloader
2. fastboot oem picoXXXXXXXX unlock, replacing XXXXXXXX with your unlock key.

Caution

If you used the original version of picounlock, you will need to restore your backed up devinfo.bin. This step was determined to be unnecessary in future releases, and was removed.

fastboot flash devinfo <path_to_backed_up_devinfo>

3. fastboot flash abl <path_to_backed_up_abl>
4. fastboot oem setenforce 1
5. fastboot flashing lock
6. fastboot flashing lock_critical
7. Boot the headset with fastboot reboot. After a short wait, Android Recovery should ask you to factory reset - do so!

Your headset should now be in a stock state, with SELinux Enforcing and a locked bootloader! If this is not the case, proceed to Troubleshooting.

Troubleshooting

Headset will not get past the bootloader

There are a few reasons for this - you can determine the issue you are encountering via running adb reboot recovery. If the headset does reboot into recovery mode, you have likely modified a partition and did not return it to a stock state before locking the bootloader. A locked bootloader will not accept this - the easiest way recover your headset is to sideload an OTA image.

If the headset does not boot into recovery mode, it is likely that you did not correctly reflash the stock ABL file. As long as you are still using the PICO Neo 3 Pro ABL file used to unlock the device, this too is recoverable. You can determine whether this is the case by how the bootloader screen looks. If you can read kona, you are still using the PICO 3 ABL.