Trapped in fastboot mode with locked bootloader and corrupted custom ROM

I want to try different custom roms to see, which one suits best for me. I was on eOS 1.81 and want to try iodeOS 4.0 now.
In the documentation it says you need to be on latest stock FW with locked bootloader - locked critical to be precise.

I was on unlock ability 0 until I found your post yesterday. Thanks to your kind help I was able to flash stock without automatic reboot, therefore unlock ability was 1. :smiling_face_with_tear:

I then sucessfully run fastboot flashing lock_critical, but afterwards the phone booted automatically and I’m back on unlock ability 0. :expressionless:

This is ok as a prerequisite for iodeOS installation, but is still very frustrating when someone wants to go back to stock completely. :smirk:

Those are two very different things!
Locked critical partitions means you can’t flash any of the critical partitions, that’s not directly tied to the state of your bootloader (you loose that ability if you lock the bootloader though).
You should not have a locked bootloader however if you plan on installing iodéOS.

As long as the OS you are installing flashes the frp partition, not sure if iodé does, you will end up with get_unlock_ability=1. Just make sure you check the state after flashing and don’t lock it if it’s 0.


Hello together,

I’m getting desperate and do not know what to do and hope someone can help me. I bought a Fairphone 4 and wanted to install CalyxOS on it. This has worked well so far. Then I restarted the phone and now have the problem that I’m stuck in a bootloop. I made it into the bootloader and the device is locked again. OEM seems to be deakvitert again, because when I get I always get an error. So I’m in the situation of having a bootloop with locked OEM and can’t unlock it via CLI. Also my attempt to install a recovery image via adb sideload fails. Does anyone have any other idea ? I am getting desperate.

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Hi and welcome, I assume your are hit by the above and the only way to unbrick is to contactsupport and send the FP4 to France…

Not sure how you installed CalyxOS maybe have a look here as well

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Welcome to the community :wave:

Did you lock the bootloader manually, the installer should protect you from bricking? :thinking:
If you didn’t, you can just run the installer again and that will take care of everything.
If you were on the latest FPOS release, you might have to wait for a few days to be able to lock it.

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

Depending on the recovery (slot) you ended up in, you won’t get far without a properly signed update, that fits the state your phone is in right now.
It’s basically a dead end.

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I got this:

(bootloader) Verity mode: false
(bootloader) Device unlocked: false
(bootloader) Device critical unlocked: true
(bootloader) Charger screen enabled: false
OKAY [ 0.010s]
Finished. Total time: 0.010s
(bootloader) get_unlock_ability: 0
OKAY [ 0.000s]
Finished. Total time: 0.010s

That’s a case for support, nothing we can do here :grimacing:

How did you lock it, that shouldn’t happen!

via Bootloader. Could i send it to them ? F*ck… i want to use it.

You’ll have to contactsupport, they’ll get you shipping labels to send it to the Cordon, the repair contractor. Will cost you 30€.

Once you get your phone back, don’t ever lock the bootloader without checking fastboot flashing get_unlock_ability beforehand.
And in the case of CalyxOS, don’t lock it manually the next time, the device-flasher checks for that and prevents you from bricking.


So, running that command where in the sequence prevents bricking?

Did you do some reading? If not I would say do this :wink: you can even search in the topic, so that you dont need to read everything


Could someone confirmed if my phone also will need to be sent to france?
Here are my details:

 .\fastboot.exe oem device-info
(bootloader) Verity mode: true
(bootloader) Device unlocked: false
(bootloader) Device critical unlocked: true
(bootloader) Charger screen enabled: false
OKAY [  0.005s]
Finished. Total time: 0.005s


.\fastboot.exe flashing get_unlock_ability
(bootloader) get_unlock_ability: 0
OKAY [  0.002s]
Finished. Total time: 0.002s

There are dozens of these threads, why has Fairphone team not addressed this fatal bug?


They simply don’t admit that it is a bug, as you can read here.

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Because they either don’t care, don’t know how to fix it or are unwilling to admit the fault exists at all since that would open them up to lawsuits.

This is a launch bug, so it’s been around for almost 2 years. If they wanted to fix this, they would have done so by now.

Hello @all !
It looks like i have to dig out my retired FP2 since my FP4 is biten by this. I do not remember locking my boot loader, but i guess it was still locked. It fails to boot to recovery or anything useful and no changes can be made to it. Any attempts to flash anything result in
FAILED (remote: 'Flashing Unlock is not allowed

Installed ROM is iodé 4.x which ran and updated fine for several months now
The point of failure was yesterday’s attempt to install Magisk via a modified ramdisk.

The most important lines from fastboot getvar all seem to be
As far as i read here, i’ll have to send it in. I only write this reply in order to be counted or noted somewhere.

When your FP4 is rooted, your bootloader cant be locked…

It failed to be rooted, resulting in this. I guess it failed because of the lock.

I think you’re unfortunately right. AFAIK in case the bootloader is locked then the boot integrity is checked - and it probably failed as you’d tempered with that.
I just wonder how you could change the boot image while the bootloader was locked… :thinking:

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I have indeed been tampering with lots of things, but the last bigger operations have been a few months back. I might have disabled OEM unlocking after one of them. It booted fine ever since, until yesterday.

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