Relock FP5 keeping LineageOS

[yvmuell]

Lineage does not support relocking the bootloader,

https://wiki.lineageos.org/faq#canshould-i-relock-my-bootloader

discussed for the FP4 e.g. here

Official LineageOS 20 FP4

If you plan on installing LOS and want to lock your bootloader you’ll have to build your own images, that’s not supported by default. Large parts of the Android security model rely on a locked bootloader and there are apps that won’t run if it’s unlocked. There are several other ROMs (/e/OS, DivestOS, CalyxOS, iodéOS) that will let you lock your bootloader, but whatever you do check that fastboot flashing get_unlock_ability returns 1 right before you lock it! Oh and welcome to the community …

Or here

Official LineageOS 20 FP4

In theory yes, but they would have to set a custom root of trust, and I checked, flashing the avb_custom_key isn’t part of the Lineage installation.