I got a used Fairphone 3 a couple of days ago and wanted to install e os.
I tried the web installer on a windows and a linux PC. Everything was fine until after it downloaded the OS. However, when i get to the step “Bootloader-Connection”, when the installer restarts the phone in fastboot mode, i cannot connect it anymore.
I read that it might be driver issues, but i cannot update them manually on the windows PC, because it is my work PC and those options are managed by our administrative team.
The fastboot menu give me the info that secure boot is disabled and device state is locked.
I found some similar questions on this forum, but most of them are really old or not helping in my situation.
Please confirm if it is a driver issue. Windows will likely install a general purpose driver not the Universal driver required. Connect the phone to Windows PC, open Device manager, check that the phone is showing OK, that is not as Problem device.
Now switch the phone to fastboot mode and perform the same check with Device manager. If showing usually you would now allow Update manager to open and to provide the required driver.
If the PC is crippled such that the cannot be resolved you will need to use a different PC.