FP3 Corrupted Device AFTER Re-Lock SOLVED rooted device (LineageOS)

Hi guys!

The process I followed is here:

  1. Fp3 Complete guide for installing lineageos (from FairPhone forum)
  2. Wiki from Lineageos for FP3 Install (official site)
  3. Fix Fastboot/Adb (Trouble with Windows 10 Pro Drivers) this guy fixed it: Fix Fastboot/Adb & Qualcomm drivers (Unbrick tool) not detecting on Windows 10/11 - YouTube
    DOWNLOAD links below this page: Fix Fastboot/Adb & Qualcomm drivers not detecting on Windows 10/11
    4: I choosed to install Lineage OS + microG + Magisk drivers.

Note: You can’t use TWRP with FairPhone 3, is not compatible.

CMD most important commands (you should replace .img and .zip files with your own downloaded link full names from the source and this files have to be saved inside Local Disk (C;) adb folder. You should first download adb-setup following the guys Youtube video mentioned above (avoid touching Qualcomm drivers, this has nothing to do with our steps, focus only in fastboot and adb).

C:\adb>sideload lineage-19.1-20221215-microG-FP3-recovery.img
(you must grant permission for this in your phone)

Load the ZIP files:

C:\adb>adb sideload lineage-19.1-20221218-microG-FP3.zip

C:\adb>adb sideload Magisk-v25.2.zip


RE-Locking your bootloader is not advisable unless you know what you are doing.

After installing LineageOS, you can lock your bootloader again. Be aware that this will wipe all your data!

If you have rooted your FP3/FP3+ and installed 3rd party Apps like Magisk, you will receive a “Signature Verification Failed” in your Recovery Mode while flashing it. This is normal since Android does not recognize this package. In this case you can’t lock the bootloader back, since your device will be corrupted and not trusted because of these third party packages!** I’d advice continue and don’t lock back the device.

If you still want to lock it and see what happens go ahead with this steps:

  1. Boot your FP3 into the bootloader with the command adb reboot bootloader
  2. Connect your FP3 with your computer and open Local Disk (C:) >adb and then run CMD.
  3. Type the command fastboot oem lock


Press power button and lower volume button together and you’ll see the screen of the bootloader. You can’t even enter Recovery Mode this time, so open CMD in your PC and type this:

C:\adb>fastboot flashing unlock

This will remove your previous OS and reset your phone to factory settings.

After this step, where people were stuck and asking for support to FairPhone or even sending back the device and asking for refund, you can fix it yourself. So don’t worry and don’t ask for refund. Go back to your previous OS and try again. Try to understand what is causing the issue. If you don’t mind, don’t perform the final step of locking back the bootloader.

Hope this helps.

Thank you,

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