Is it safe to relock FP4 after e/OS/ installation?

After following guide and reading Fairphone - FP4 - FP4 - Documentation Suggestions - #158 by Ulix, I am wondering if it is safe to relock the bootloader?

e/OS/ is installed (and works) on the FP4, but the bootloader is still unlocked and I am not sure if it is safe to lock it again or not.

Version 1.14-s-30340816320616-stable-FP4
Android Security Update 5 July 2023
Vendor Security Patch Level 5 June 2023

Does the vendor patch level here refer to the e/OS/ security update? How can I check the version of this if not?

I am not sure if it is alright to relock or not after reading the “Caution” section of and do not want to brick the phone :sweat_smile:

Thank you.

It’s a good thing you bring this up.
Always before locking the bootloader, check the result from “fastboot flashing get_unlock_ability"
If the result is 0 don’t lock the boatloader as you will brick your phone.

This is happening on Fairphone 3 and it’s not clear if this is also the case on the Fairphone 4.
Better safe then sorry.

It depends on what you had on the device before you installed /e/. So for example, if you were on Stock Fairphone OS and were fully up to date it would have been on August security patch level.

Do not relock bootloader in this scenario but wait until /e/OS catches up or overtakes it. The down side is that locking/relocking wipes data so you would have to set your phone up again.

As Lidwein suggests, always check the unlock_ability but getting “1” as a result only means you will be able to unlock again; it is not a guarantee that the phone will boot into the OS.

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