@mrt10001 Thanks for your quick response. I forgot to mention it, but I couldn't even boot into fastboot the manual way. I actually figured out the issue. It seems it was the USB cable after all, because two of my cables refused to work, even though they normally work fine. I used a third, through USB-2 as well and were luckily able to fastboot the manual way only. It was also very quick and easy to install lineageOS, so I already have that now. Thank you for your help

Hi everyone

I have installed Ubuntu Touch on Fairphone 4, everything worked perfectly. Unforunately after trying it for some time, I have decided it is not for me. I am attempting to install LineageOS instead, which requires me to boot into fastboot mode. This requires me to have USB debugging enabled, but even though I did enable Developer Mode on the phone, the phone is not recognized when i use

adb devices

The output is

List of devices attached

I have tried plugging it in USB-2, USB-3, USB-C ports, even different computers. Nothing works and adb can not recognize the phone. Does anyone have an idea on how to solve this issue? I even tried Erase & Reset All, and reenable developer mode with no luck.
Any help is appreciated, thank you.