FP3+/LOS 19 - stuck in fastboot loop


I installed LOS 19 (android 12) on my recently purchased FP3+ and been using it for a while without problems.

Then I needed to root it so I could run some apps that require root access.

It did not work and now the FP3+ gets stuck in a boot loop in the fastboot mode, with a screen display somewhat comparable to this one here (apart there’s no BOOTLOADER VERSION and BASEBAND VERSION displayed and some lines such as HW_CHIP and GEN_PACK are not here).

Whatever action I choose, I revert back to the same screen.

From my Ubuntu 22.04 computer, I can’t connect with adb, but fastboot can do things on the FP3+ such as reboot the FP3+.

For instance, here what’s displayed when I try to flash boot the LOS19 recovery image:

$ fastboot flash boot lineage-19.1-20220822-recovery-FP3.img 
Sending 'boot' (65536 KB)                          OKAY [  1.607s]
Writing 'boot'                                     FAILED (remote: 'partition table doesn't exist')

The remote error message ‘partition table doesn’t exist’ lend me to this post.

I followed the suggestion to flash again TWRP which I downloaded as of version 3.6.2_9-0:

$ sudo fastboot boot twrp-3.6.2_9-0-FP3.img 
Sending 'boot.img' (30924 KB)                      OKAY [  0.743s]
Booting                                            FAILED (remote: 'unknown reason')
fastboot: error: Command failed

Then I tried to follow the guide FP3(+). Install Fairphone OS offline where we can read in the Preliminary steps:

  1. Download onto your computer (pay attention to Android version):

- Fairphone OS (Android 11) -

Pay attention to Android version, alright but where can I find the …fastbootimage.zip for Android 12?

In other words, is there a way I can boot again my FP3+ under LOS19 as installed since some days now?
I’d like not to loose all my stuff on it, BTW.

Thanks for reading.

I think I’m making progress…

I understand the reason why I got to this loop is that, when I used the previoulsy mentioned guide FP3(+). Install Fairphone OS offline, I landed on a boot screen telling me:

Android Recovery

Cannot load Android system. Your data may be corrupt. If you continue to get this message, you may need to perform a factory data reset and erase all user data stored on this device.
Try again
Factory data reset

The only way I had to exit this, was to remove the battery, then I booted back in fastboot mode.

Am I wrong to thing the boot image is wrong and I should flash a correct one?

Where can I find a correct boot image that would allow the smartphone to get back to LOS19 as still installed (I guess)?

can you go boot from bootloader into recovery and then do the factory reset or try again? in the recovery you can navigate up and down with Vol Buttons and with power you would confirm what you want to do. I assume factory reset should be no issue as you had done one before you installed LOS?

Thanks for replying @yvmuell

A factory reset means loosing all my data, which is something I want to avoid, as much as possible.

But I guess I just sorted it out. I’ve just been able to reboot it back to my previous install, and I get all my data.

Here’s what I did:
(I remembered the active slot was b)

fastboot --set-active=b
fastboot flash boot twrp-3.6.2_9-0-FP3.img

Then I was able to boot to TWRP.

Under TWRP on the FP3+ I went to Advanced > Sideload (did not tick the wipe options) and then on my computer did a:
adb sideload lineage-19.1-20220822-nightly-FP3-signed.zip

After it was done, I just rebooted the FP3+ and… voilà, all is back on rails (at least it looks like it is).

Maybe I need to check this story about slots, because I saw the sideload was done on slot a, while before it was on slot b…

And then, but it’ll be another thread: what’s the way to root a FP3+ under LOS19?


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