Restoring stock OS after unsuccessful LineageOS (iodé) install

[hirnsushi]

Could you post the output of fastboot oem device-info please so we can get a clear starting point

@Wallby

I’ve tried running the iodé OS installer again, which works except that at the end it errors saying “boatloader already locked”.

That’s an interesting failure, I wonder what they’re checking against that makes that message trigger for your phone. I can’t find sources for the iodé installer on their GitLab though, no idea where those are…

@Wallby

Am I really required to send my phone to France now for them to unbrick it?

Since you’re still able to (somewhat) successfully run the iodé installer I’m pretty sure this is fixable, we just need to find the specific issue

@Anonymous9090

Pretty sure its possible to flash stock even with locked boot loader.

No, if the bootloader is actually locked (which it doesn’t appear to be in this case), then you lose access to fastboot flash etc., changing a variable in the install script won’t magically enable those commands again.
In the case of an unbootable system with a locked bootloader and get_unlock_ability at 0 the only way out is EDL-mode, and the community doesn’t have the keys for that (at least not for the FP4), only Fairphone can fix a phone that’s fully bricked.

@Anonymous9090

1. INTEGRITY_CHECK=“false” (Do not detect you’ve been editing this script)

I would also strongly advise against disabling integrity checking, because that also makes sure that the partitions you are flashing to the phone actually match what is expected.
The proper route is changing the checksum for the install script in the right location:

@hirnsushi

you have to run sha256sum flash_fp4_factory.command to generate a new checksum, then search for flash_fp4_factory.command in the SHA256SUMS file, and finally replace that line with the new checksum.