That's not a supported setup or possible atm.
postmarketOS
postmarketOS - a real Linux distribution for phones and other mobile devices π§ π± π©βπ»
Rules:
- Be nice, follow CoC
- Donβt ask for device ports, consider DIY
- Report bugs in the issue tracker (not here! π)
See also:
Only pixels let you relock the bootloader after flashing.
Frustratingly, grapheneos only supports pixels because of that.
That's just plain wrong. Some others also allow it, for example: you could lock a Fairphone.
After installing a different os? So if I installed PostmarketOS, could I lock the bootloader? After looking in to it more, it seems like a pretty clear no.
postmarketOS does not seem to have implemented Android Verified Boot yet and I am not aware of Linux distros that do it.
Have a look at iodΓ©OS, CalyxOS, GrapheneOS if you want that, at least for now.
I have Graphene, and I'll be sticking with it for now.
I think my next step will have to be getting involved with implementing verified boot, because unless every phone suddenly starts shipping with TPMs and open bootloaders, I won't ever be able to switch.
Finding a starting point is half the battle I guess!
There's definitely enough to do, so if you want to contribute in that area, it'd be MUCH appreciated. :)
My experience with the FP4 is you can only lock the bootloader with a couple of "official" distro's. And even then there are conditions where this can go bad.
I can use the default factory version provided by fairphone, I can use e/os.
While I can install and use postmarketos or a lineage image, I can't lock the bootloader without turning it into a brick. I believe it is to do with boot partition signing by the CPU manufacturer and the android bootloader checking it.
i think it's simpler than that. It merely stores the latest security update you had when you locked your bootloader and doesn't allow you to rollback to an earlier version,but anything newer - regardless of the ROM being official or eOS/iodΓ© , would allow you to relock it.
TLDR: flashing ROM security patch version > your existing security patch version.