FP4 softbricked, need info on recovery methods

/e/OS Devices Fairphone
,
1

Currently attempting to walk back mistake.
Fairphone 4 was compromised by file attachment in email I received, so I did reset on phone and factory reset it.
Now with blank phone, tried out multiple OS’s on it, settling on lineageOS.

I made the mistake of following the optional step in the FairphoneOS installation tutorial for locking bootloader both critical and non-critical.

current nonstock images installed are dtbo.img and recovery.img which are paired with lineage-22.1-20250122-nightly-FP4-signed.zip in fairphone 4 download page for lineageOS 22.1.
I am using adb version 1.0.41 and fastboot version 28.0.2-debian

I’ve looked over e/OS’s bootloader instructions, read through the “fp4: another brick in the wall” (I would link it but I am only allowed two links as a new forum user) and the links provided there. I also read the XDA Forums post titled " [Solved] Is it possible to relock the bootloader after installing a custom OS?" (after the fact) and saw them talking about a software called MSMDownload for unlocking/relocking quallcomm CPU-based devices, though it’s not clear how to use it for a Fairphone.

bootloader reads:

FastBoot Mode
Product_Name - FP4
Variant - SM_ UFS
BOOTLOADER VERSION -
BASEBAND VERSION - 
SERIAL NUMBER - <phone serial number>
SECURE BOOT - yes
INTERNAL STORAGE SIZE - 240GB
MAIN MEMORY SIZE AND VENDOR - 8GB UNKONW
DISPLAY PANEL NAME - DJN <display panel name>

when I type fastboot flashing get_unlock_ability I get < waiting for any device > indefinitely with no response while in recovery with adb enabled, but when in fastboot mode I get:

bootloader) get_unlock_ability: 0
OKAY [  0.000s]
Finished. Total time: 0.000s

typing fastboot flashing unlock I get:

FAILED (remote: 'Flashing Unlock is not allowed
')
fastboot: error: Command failed

Currently at a loss on which way to proceed.
Regain your privacy! Adopt /e/OS the deGoogled mobile OS and online servicesphone

2

Quite a few things going on there!

Please include output of

fastboot devices

This helps rule in or out

  • difficult situation
  • phone not talking to you

Late Edit

As you have fastboot talking, you should not have to take this route yet, as I understand this is not documented for fp4 and should the worst happen the phone has to be returned to Fairphone or their agent for reimaging,

3

fastboot devices returns:
7c4a9ebb fastboot
so the device is replying

4

I guess I am still not sure of the timeline :slightly_smiling_face:

Was or is working or failed ??

Are you unable to get into the device to check USB debugging and the status of OEM unlock ?

Install LineageOS on FP4 | LineageOS Wiki indeed does not invite you to lock bootloader.

With a view to installing /e/OS ??

It cannot be unlocked from fastboot when the device is locked.

I am not suggesting you do this right now; just asking till I understand the situation, did you try Factory reset ?

5

Here is a discussion about a similar issue:

6

Was or is working or failed ??

The install was successful and the phone would boot into lineageOS no problem, prior to the bootloader being locked.

I followed this optional final step in fairphone’s " Manage the Bootloader" page, not aware that step was unsafe with third party OS’s.

… did you try Factory reset ?

I have tried factory reset through the recovery menu. I boot to bootloader → Enter Recovery mode → factory reset → Format data/factory reset → format data
I am given the following output:

-- Wiping data ...
ERROR: recovery: Open failed: /metadata/ota: No such firle or directory
Formatting /data...
Formatting /metadata...
Resetting memtag message...
Data wipe complete.
7

From my point of view this situation cannot be easily recovered. On the FP3 the critical partitions are unlocked and you can unlock the non critical partitions by flashing the devinfo partition:

fastboot flash devinfo devinfo-unlocked.gpx

This solution isn’t avalable for the FP4. You have to use the EDL (Emergency Download Mode) to make a recovery. This can also be done by the Fairphone support for around 30 €.