FP3+ no USB conection via fastboot, unlocking bootloader not possible

[Ingo_FP_Angel]

@ThibaultD

6- put your FP3 in fastboot mode and connect it to your PC with a USB-C cable that can transfer data. Then in the Powershell window, type ./adb devices , your FP3 should be listed (note : my FP3 was not listed but I followed the remaining instructions)

There’s either a typo or mistake in this step. When the phone is in fastboot mode, adb commands do not work (they only work in recovery or system mode). I guess you meant ./fastboot devices which would be correct.