I had to wait a few weeks but now my Fairphone 4 is running an up-to-date e/OS (thanks to the Android anti-rollback feature) with its bootloader locked. Sad thing is I had to reinstall everything because all my data has been erased when I re-locked the bootloader (totally forgot about this, this is a PITA). Anyways, I've been using it for some weeks now but I'll wait one week or two more before publishing an honest review. #fp4