Upgrade to OTA 8 (from OTA7, stable) interrupted on FP2

[Aloys]

Hello,

I launch the automatic update on my FP2 (from OTA7 on stable channel), download was ok, it reboots and during the update process, it stops (black screen, pwr button has no effect) probably because of the battery.
I had around 55% of battery, but in the past I already had FP2 battery suddenly dropped.
Of course, I should have connected the power cable!

Now when I reboot, I am stuck in the "boot" screen (Fairphone Powered by Ubuntu...).

What is the best way to recover without loosing my data, do you think I should try the UBports iInstaller?

[AlainW94]

@ublublu try to flash the recovery then boot on it and rerun ubports-installer without swiping data. this can maybe help

[Aloys]

@AlainW94 thank you, but how do you "flash the recovery then boot on it"? is there a documentation somewhere?

[AlainW94]

@ublublu you have to start the phone on bootloader usually power and vol down button hold at the same time until the scene display the fastboot message then using fastboot flash recovery [name of the recovery file]. or you can also try directly to start in recovery by holding at the same time vol up and power button. if you got the recovery screen, then start the ubports-installer. they are some thread about flashing a recovery for your phone over the net. sorry I don't have your model then I can't give you the precise procedure

[Lakotaubp]

@ublublu I would switch of and fully charge the battery then try again while connected to power. I have had a nexus stick here before then suddenly start ok. see if you can boot to bootloader and start from there. If all else fails rerun installer and DO NOT select wipe option.

[Aloys]

@Lakotaubp, I fully charged the battery as you said, but it was the same problem, it was stuck in the first screen.

I tried to start the phone on bootloader by holding pwr and vol down buttons, but I never succeed!

I tried UBports installer, but last version 0.1.21 does not work with my FP2, I have the issue:
Fastboot: Unknown error: downloading 'boot.img'...OKAY [ 0.360s]booting...FAILED (remote: bootimage: incomplete or not signed)finished. total time: 0.361s

I add this problem before, see:
How to manually upgrade from OTA-3 to OTA-4 and @advocatux suggested to use the UBports installer V0.1.12.

I launched this version and it finally works!
I had to select manually the device to FP2, because device was not automatically detected. I reboot with pwr+voldown or pwr+volup+voldown buttons several times, after several reboots, it succeed to detect the device, and the update procedure went till the end successfully.

Now I have the OTA 8 and all my data.

Thank you @AlainW94 and @Lakotaubp

[Lakotaubp]

@ublublu Glad your sorted, enjoy.

[AlainW94]

@ublublu congratulation