Device corrupt message after locking bootloader despite get_unlock_ability = 1

Help Fairphone 5
,
1

Hi forum, I’ve switched to iodéOS from an /e/OS ROM setup on FP5. I checked bootloader lockability using

prompt:~$ fastboot flashing get_unlock_ability
(bootloader) get_unlock_ability: 1
OKAY [  0.000s]
Finished. Total time: 0.001s

Unfortunately, after locking, the device shows as corrupt and won’t boot. After that, I tried reverting to /e/OS, to Stock ROM, and once more to iodéOS, and consistently the same behaviour emerges.

  1. Why would the device say it’s corrupt even though before it says it’s lockable?

  2. How do I fix this?

Cheers for help!

2

As I understand it, when you lock the bootloader, the phone will test if the rom is properly signed. Most custom roms aren’t.

The get_unlock_ability only tells you whether you are allowed to unlock, not whether locking will work.

You should still be able to get into fastboot. If you can then unlock the bootloader, it should be possible to recover.

3

Well, I did have a locked bootloader before, and now I can’t even lock it with stock ROM.

Recovery to any OS from fastboot is not the issue, re-locking the bootloader after recovery is…

4

Source? And whats the solution?

5

Which Iode Version and did you check their forum if there are issues reported for this version?

6

The solution for not signed roms, like the community /e/os ones, is to NOT relock the bootloader.

7

I didn’t, but as I couldn’t subsequently relock on reinstalling /e/OS or Fairphone stock ROM either, I figured it’s not an iodé problem per se…

8

Well then the statement is wrong because official e/OS as well as Iode normally are lockable, while LOS is not.

9

Source? And whats the solution?

I don’t understand the details, but try reading here:

10

Hi,
If the unlock ability is 1 then you should be able to $fastboot flashing unlock

To lock successfully you need to make sure the SPL of the new one is the same or newer than the one previous.

You need to make sure that you’re using official /e/os build and not community. Official /e/ is signed.

Lastly, you should be able to install/e/ with an automated installer that should work and lock without your input.

11

Exactly, that is my understanding. So, from latest /e/OS, I installed latest iodé (which I thought isn’t older than /e/OS), then locking failed and corrupted the device.

After that, back to the previous /e/OS version, which should be OK because it can’t be older than itsself, but same problem. Then to Stock OS, same problem. Then iodé again, no luck.

What do I do from here?

12

Thanks the initial statement isnt correct when you wanted to say that locking is not possible/supported. Locking Iode is possible without issues normally.

13

Ah, your target is iodéOS?
Then the automated installer should be able to lock the bootloader for you. You just need to accept.
But really really compare each installed version and note their respective SPL please.

14

Yes, I didn’t intend to say anything about iodéOS specifically, but I can see how it can be understood that way from the context.

15

Yes, the automated installer did lock the bootloader. This started the issue with the phone shown as corrupted.

Now I cannot relock the bootloader on any of the ROMs.

How do I fix it? Can I somehow check the rollback index? Will it work after next update? What should I do?

16

First off, you’re somewhat OK not having a locked bootloader for a while. I would rather have an unlocked bootloader for a few weeks rather than a brick for the rest of my life.

My first assumption would be a SPL issue.

IodéOS changelog indicates an August 2025 SPL (as of Sept 5th, not sure, maybe @yvmuell can confirm the SPL for current iodéOS)

Latest stock (VT2D) images from Fairphone 5 have an August SPL too.

/e/OS is now at /e/OS 3.1.4 and boasts a September 2025 SPL.

So, you have installed an /e/OS with, presumably a september SPL. You cannot lock on current iodéOS nor latest stock.

You could lock on current /e/OS, though. You should be able to.

17

Oh, very good spot. Didn’t see September for /e/OS, that would be the reason then!