Fairphone 4 bricked when going back from iodéOS to FPOS

[citroniais]

Hi everyone,

I’ve been having bugs with my FP4 for some time (touch screen, microphone, etc.). As I was on iodeOS, I wanted to switch back to FPOS to see if the bugs persisted. If so, I would’ve sent the FP4 to warranty repair.

So I started by enabling OEM unlocking, did fastboot flashing unlock and fastboot flashing unlock_critical and then flashed FPOS (FP4.SP2J.B.086) with the script provided here : https://support.fairphone.com/hc/en-us/articles/4405858261777-Fairphone-4-OS-Manual-Installation.
I had trouble because the script often freezed during the flash, but after running it several times, it finally worked.

FPOS started, I did the initial configuration, enabled the developer settings, went back into fastboot and did fastboot flashing lock_critical, at which point it restarted and reset itself. I gave it time to reboot, but I didn’t do the initial configuration this time. I restarted the phone directly by keeping “Volume Down” pressed, which made me restart in fastboot mode.

I did fastboot flashing lock, the phone rebooted and immediately displayed “<!> Your device is corrupt. It can’t be trusted and will not boot”.

Now it’s boot-looping to fastboot. I’ve managed to access the EDL mode, but it seems that no way of unbrick has yet been found via EDL.

If you have any information that I missed, and that might help me, please let me know (poke @hirnsushi, as you seem to be the person with the most knowledge of EDL for the FP4).

In the meantime, I’m going to contact support, as I know they’re not very quick to answer

Thanks in advance to anyone that will give me any clue to solve my problem.

PS : Here is the error code I encountered (picture found on internet, not a FP4) :

[hirnsushi]

I’m sadly not aware of any news regarding EDL either, sorry.
What’s the output of fastboot oem device-info && fastboot flashing get_unlock_ability rn?

@citroniais

FPOS started, I did the initial configuration

Here’s where it went wrong, don’t boot into Android after flashing the system, the first boot resets get_unlock_ability.
Always check that value before doing anything bootloader related.

[citroniais]

@hirnsushi

What’s the output of fastboot oem device-info && fastboot flashing get_unlock_ability rn?

> fastboot oem device-info
(bootloader) Verity mode: true
(bootloader) Device unlocked: false
(bootloader) Device critical unlocked: false
(bootloader) Charger screen enabled: false

> fastboot flashing get_unlock_ability
FAILED (remote: 'unknown command')
fastboot: error: Command failed

@hirnsushi

Here’s where it went wrong, don’t boot into Android after flashing the system, the first boot resets get_unlock_ability.
Always check that value before doing anything bootloader related.

Oh, okay… It’s sad that Fairphone does not include any of this information in their docs.

[hirnsushi]

That doesn’t look good
Strange that the second command failed, are you in fastbootd by any chance? But if fastboot flashing unlock doesn’t work it doesn’t really matter anyway.

@citroniais

It’s sad that Fairphone does not include any of this information in their docs.

Yeah, given how easy the FP4 is to brick you’d imagine someone would improve the documentation, but here we are over a year later and it’s still lacking.

(Or, you know, implement safeguards right in the installer that checks for that and locks afterwards, like Calyx does)

[yvmuell]

The worst is that Fairphone just does not seem to know about this problem, seeing recent comments which leaves me puzzled the least

Question about returning to Stock OS

Thanks for the explanation. I will have a look in the next weeks and see, if I am going that route or just wait for the updated images from FairPhone. Just received info from support: Blockquote I was referred by out department that, technically, Fairphone OS is not supposed to brick because of locking with older security patch. However this hasn’t been tested for the last few updates, so we can’t guarantee it. If you don’t want to wait for the next update, you can try locking the bootloade…

Fairphone 4 software issues

Hello loseyourself! Hmmm, I’m not sure I fully understood your question. But if I got it right, your complaint has to do with the fact that locking the bootloader may brick the phone. If that’s the cause, then we’ve confirmed it before: installing software with an older security patch than the one you had before will trigger Android Rollback Protection. This is a well-established security feature since Android 6 and we’ve made numerous warnings about it. It’s in our support arti…

[citroniais]

@hirnsushi

Strange that the second command failed, are you in fastbootd by any chance?

I’ll give it a look tomorrow

@hirnsushi

(Or, you know, implement safeguards right in the installer that checks for that and locks afterwards, like Calyx does)

That could be an idea… But it seems to be too difficult for the FP Team

@yvmuell

The worst is that Fairphone just does not seem to know about this problem, seeing recent comments which leaves me puzzled the least

It’s not even written here…

Fairphone 4: Public Issue Tracker

[citroniais]

@hirnsushi

Strange that the second command failed

Maybe I typed it wrong, or that was an issue with Windows, idk. I don’t think I was in fastbootd, I just started the device and it went to fastboot mode (because bootloop to fastboot mode).

I tried on Linux Mint, and here’s the output :

> fastboot flashing get_unlock_ability
(bootloader) get_unlock_ability: 0
OKAY [  0.001s]
Finished. Total time: 0.001s

What does this zero means?

[Ingo]

In computing, “0” usually means “false” and “1” means “true” in the context of some question with a binary answer (“can the phone be unlocked?” in this case).

[citroniais]

After one month, I finally have my FP4 back !
I didn’t have to pay anything, fortunately…
One month is quite a long time, especially considering that the phone stayed 2 days at the repair center.
They also changed my screen assembly, for the ghosting problem I had.
I re-installed iodéOS, their script is so nice compared to the Fairphone’s one, and their instructions are simple enough (maybe not enough detailed).
I just saw that Fairphone updated their tutorial, but it seems to be much less complete than it was before, and there seems to be no mention of the fastboot flashing get_unlock_ability command…

Anyway, thanks everyone for your help !