thanks for your answer.
In fact, I’d like to have TWRP back again and accessible by the hardware-buttons. So I installed TWRP again, but it doesn’t work… Fastboot works, I can even install /e/ with it (which works, but not the sensors). But adb seems not to connect… For adb reconnect it gives no devices/emulators found back… And I am still with the UBports recovery…
How can I uninstall that?
Ah, I think I see a possible problem.
The “Fastboot Install Method (No Root Required)” begins with the device booted and with Android running.
Forget the “adb reboot bootloader” part and just start or reboot the phone while keeping the Volume - button pressed to boot the phone into Fastboot mode (aka bootloader).
Then you can continue at “You should now be in fastboot mode” .
ADB works when Android is running and USB debugging is enabled in the settings … and it works when TWRP is running, but only with a subset of the possible commands … and recovery programs tend to support ADB Sideload to install stuff, but you have to switch them into receiving mode for ADB Sideload first, so the computer can push the install file to them.
By successfully installing TWRP, or any other recovery program.
I don’t recommend formatting the recovery partition because it simply is not necessary … and you would still have to install a recovery program if you want to have a working recovery mode.
Fastboot is not recognizing your phone.
Is the phone connected to the computer and booted in fastboot mode (only the Fairphone logo is displayed, with current modem files additionally the blue LED would be blinking and at the start the phone would have vibrated a few times)?
You “just” need to get the fastboot command to work somehow, as it seems booting into fastboot mode still works.
Can you try on another computer? Windows preferrably (tends to give less trouble with this)?
Keeping the power button pressed for approx. 15 seconds should force a reboot.
It would be good to be certain the phone is really in fastboot mode and not just hanging while trying to boot.
Do you still get into the UBports recovery by keeping Volume + pressed when starting or rebooting the phone?
(This recovery takes a while to start.)
There should be an option somewhere to reboot to bootloader or fastboot mode. That should definitively reboot the phone into fastboot mode.
Then … If fastboot on two different computers doesn’t find the phone in fastboot mode, there could be something wrong with the cable or with the USB port of the phone … which reminds me …
Awesome hint! Yesterday it was too late, I didn’t see it anymore and was too tired, but this morning with a fresh head I tried to boot into recovery - and TWRP is there!
I think from there we can try to manage something… I am looking now into it.
Cool, yeah, that works! Thanks for helping me understand that better!
True. In fact TWRP was happy (installation successful), but when I start /e/, it is like a fresh install (I need to set up my accounts and my settings etc…). It this normal for an TWRP backup? I was aware that /data/media is not backed up, but I thought I could go back to my set up system…
I heard about LOS 17.1 being out for the FP2. So I thought, if I already have to reinstall everything, I can flash LOS 17.1 just to give it a try and go back to /e/ later. The installation went well with the LOS recovery, and now I am running LOS 17.1 - and the best thing: SENSORS WORK AGAIN! As @stanzi I can’t explain why, but they work! The first time that I could use the Calibration Tool! I hope the sensors will keep working when I go back to /e/ … but that will be another story for another day.
Big THANKS to @stanzi and especially @AnotherElk for the great help and taking the time to think and try on their side!!!