Oh sorry, my badā¦ @Corentin and @Conatus are trying to return to FP OS with GMS. They did try with method 1, but it didnāt work. So I told them to try method 2 ! But for Windows commands, I have to guess or the make researches, as I donāt know the Windows Command Prompt at all (I am on Linux).
As you seem to be a Windows user and to know cmd, I thought you could help them to navigate through the files with this tool.
Normally yes, because I used it for Lineage OS But Iām not really sure, as there is āotaā in the filenameā¦ Nevertheless, it is a ZIP file and it should work with TWRP. Iām doubting too much
Oddly enough, the official guide recommends this method. Iām not sure whether it does a wipe of user data, which would mean youād need an SD card or this sideload approach.
Edit: I read over the big red warning box (see below) - data is wiped, which would take out the update file that youāre trying to apply, unless you have it on a SD-card. As not everybody will have one, sideload is recommended.
Warning:
If you switch to Fairphone OS, all your data (including apps, messages and pictures) will be erased. Make sure to backup first!
Are you sure the word sideload is actually in the error messages?
If the word sideload isnāt in the error, then adb is just saying it doesnāt know the file youāre pointing to. Two ways to fix it: copy it (FP2-gms76-1.13.0-ota_from_open.zip) into the folder where youāre running adb (probably the easiest option), or modify the command to have the full path for the file name (for example adb sideload 'C:\Downloads\FP2-gms76-1.13.0-ota_from_open.zip')
For the console to find a programme, it needs to be installed and in a place where the console knows to check for programmes. The console will always check the folder in which you are currently working, so it is perhaps easiest to:
navigate to the folder where you installed adb
copy FP2-gms76-1.13.0-ota_from_open.zip into the folder
hold shift and right click on some empty space in the window (not on a file), select open terminal here (or your language equivalent).
I donāt think you need the full Android SDK. Iām not familiar with the universal adb driver, so it may install adb somewhere, but based on this topic (step 2), it doesnāt. The guide in that topic recommends minimal adb.
You may need to start the phone normally (so not in TWRP) and authorise access from there (and then restart into TWRP to continue).
Iād hope so. Iām still wondering whether a manual download of the ota file, and then opening that with the updater app wouldnāt also work. Presumably the way the updater works (and TWRP should as well) is to copy the update file into the cache partition.
But now, something is wrong. It start, with the Fairphone and the Android logos, next it make the animation with the āstart a mouvementā, next again it say āLoadingā and next it optimise apps. But now tiās blocked here ā¦
And I try to wipe factory settings / data but it do the same. Now Iām just waiting if it can unblock of āLoadingā.
If it doesnāt fix itself, see if there are options in recovery mode to wipe Dalvik cache and normal cache, then reboot. Or perform a factory reset.
Iām not as familiar with the FP2 side as I am with the computer side of working with adb etc, so Iām not sure whether there are any other tricks.
I donāt recall anyone on the forum posting a similar issue, so Iām not sure what could be causing it.
If you have an SD card in the phone, try removing it and seeing if it does start then.
If that doesnāt work, the only thing I can think of would be flashing new firmware using fastboot. You may want to see if anyone else has a better idea first though. If you do decide to try, the method is described under method 4 on the manual instructions page. You can skip installing drivers and adb/fastboot as you already have those. The .bat file included with the images calls fastboot, so you may need to move the unpacked files to where youāve installed adb/fastboot.
It might be worth copying the files from the SD card onto a computer, then formatting the SD card in the phone and finally copying the files back onto the card. Sometimes this helps, but sometimes the underlying cause is a defect in the SD card (which a format wonāt solve).
@Corentin and @Conatus are trying to return to FP OS with GMS. They did try with method 1, but it didnāt work. So I told them to try method 2 ! But for Windows commands, I have to guess or the make researches, as I donāt know the Windows Command Prompt at all (I am on Linux).
But Iām not really sure, as there is āotaā in the filenameā¦ Nevertheless, it is a ZIP file and it should work with TWRP. Iām doubting too much 
Warning:
