Returning to FPOS from LOS fails

[christian99]

Hi, I used LOS on my FP4, now I have FP5 and want to pass on my FP4, therefore I try to install FPOS on it.
I’m trying to follow this article: https://support.fairphone.com/hc/en-us/articles/18896094650513-Install-Fairphone-OS-manually
and also have (as far as i can see) successfully unlocked bootloader according to https://support.fairphone.com/hc/en-us/articles/10492476238865-Manage-the-Bootloader
fastboot oem device-info shows this

(bootloader) Verity mode: true
(bootloader) Device unlocked: true
(bootloader) Device critical unlocked: true
(bootloader) Charger screen enabled: false
OKAY [  0.001s]
Finished. Total time: 0.001s

When I run the flash_fp4_factory.command script, it finds the phone, but then the script exits with no further hint why.
I already tried to see, what’s failing by running the script with bash -x and I could see, that
fastboot oem device-info fails with

fastboot oem device-info
FAILED (remote: 'unknown command')
fastboot: error: Command failed

After a little bit of experimenting, it turns out, that some/most(?) fastboot commands fail, if they are executed too quickly.
So I added a sleep 5 before every fastboot call in the script, (waiting 1 or 2 seconds didn’t work reliably, only 5 did).
This helped me through the initial detection part of the script to the point, where stuff should be actually flashed, but then it hangs:

+ /usr/bin/fastboot -s d996abe2 flash abl_a /home/chriss/android/fp4/FP4-TP2N-factory/images/abl_ecc.elf
Warning: skip copying abl_a image avb footer (abl_a partition size: 0, abl_a image size: 155648).
Sending 'abl_a' (152 KB)                           FAILED (Status read failed (No such device))
fastboot: error: Command failed
+ echo -en '\033[1;31m'
+ echo 'ERROR: Could not flash the abl_a partition on device d996abe2.'
ERROR: Could not flash the abl_a partition on device d996abe2.
+ echo ''

+ echo 'ERROR: Please unplug the phone, take the battery out, boot the device into'
ERROR: Please unplug the phone, take the battery out, boot the device into
+ echo 'ERROR: fastboot mode, and start this script again.'
ERROR: fastboot mode, and start this script again.
+ echo 'ERROR: (To get to fastboot mode, press Volume-Down and plug in the USB-C)'
ERROR: (To get to fastboot mode, press Volume-Down and plug in the USB-C)
+ echo 'ERROR: (cable until the fastboot menu appears.)'
ERROR: (cable until the fastboot menu appears.)
+ abort_now
+ echo -en '\033[1;31m'
+ read -rp 'ERROR: Aborting now (press Enter to terminate).' a
ERROR: Aborting now (press Enter to terminate).
+ echo -en '\033[0m'
+ echo ''

+ exit 1

the script hangs forever on Sending 'abl_a' (152 KB) without any progress seen neither in terminal nor on phone itself.
the FAILED was a result of when I rebooted the phone.
As the phone seems to boot fine afterwards I would guess, that nothing was actually written to the phone.

Another thing I noted:
Sometimes™ when running fastboot, the phone leaves the fastboot screen and shows the Fairphone screen, that’s also seen when regularly booting. It has a tiny message, “Press Power to turn off” or similar.
This can happen either when running fastboot manually or sometimes, too, when the script runs.
I couldn’t determine a pattern, when this happens, but I have suspicion, that’s not intended.

So, long story short: What can I do to get FPOS installed? I have suspicion, that something is quite wrong here, but I don’t know what, or how to fix it. Some help in finding out what is wrong here would be appreciated.

BR, christian

[JohnnyD]

Have been following this thread as well? Essentially the wrong USB cable was the culprit. It sounds a little bit like this is the case with you as well.

Phone stuck in fastboot mode, unable to install Fairphone OS

Hi, I recently got a Fairphone 5 and wanted to install e/os on it. I had thought I could do it through the easy installer but found out after buying that wasn’t an option yet. Anyway, I wasn’t too put off and read the instructions carefully and then tried to step through them. Long story short, the installation didn’t work. It’s stuck in the bootloader menu (it gives me the four options start, restart bootloader, recovery mode, power off, but choosing any only loops it back to this screen). It …

Furthermore there are other/similar forum threads here discussing the topic of “returning back to FPOS” you may want to check out as well.

e.g.

Reinstalling Android After Installing Ubuntu Touch

Hello, I have installed Ubuntu Touch (maintained by Ubports) and I wish to go back to FPOS and relock the bootloader. I am unsure how to proceed with this because I am aware of risks with locking the bootloader after flashing different OSs. How would I proceed with this? I received my FP4 with the Android 11 version of FPOS, but I am wondering if there is a flashboot command that can confirm this.

[christian99]

Hi, thx for your answers. I did read a few other threads already, but not the one with the cable, probably because it is tagged FP5.
I did already try it with two different cables, but there was no difference. I will try to get a different one to try it out.
Curiously, the two cables I used show otherwise no problems at all. Mainly, I use them for charging, but occasionally for data/file transfer, too. Up to now, no problems whatsoever occurred (at least I didn’t notice any). So I’m wondering, maybe they are just “broken”/worn, because they are already several years in use, or maybe they lack some kind of “feature” (is this the appropriate term in this case) that is required for this. What could that be?