Can't unlock critical partitions

/e/OS Devices Fairphone
,
1

Hi!

I purchased a Fairphone 6 with a preinstalled Android 15. I want to switch to /e/OS. I updated Android, I unlocked the bootloader, I activated USB debugging, following the instructions on the support site. The web based installer ( /e/OS Installer ) didn’t work (“Cannot connect ADB No device connected”), so I downloaded the installer to my Ubuntu laptop and tried from the command line. It copied and apparently installed many images, but failed eventually. I got the message:

Error: Critical partitions are still locked.
Did you execute ‘fastboot flashing unlock_critical’?

Unfortunately, unlocking the critical partitions doesn’t work either:

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

The flags --disable-verity and --disable-verification didn’t help. A factory reset in Recovery Mode also fails with a permission error. The phone is presently stuck in a boot loop. I cannot even reinstall Android. How do I get out of this?

Any help is welcome!

Hi i'm new and which android to /e/OS version i need?
Fairphone6 stuck on Murena logo after flashing to : IMG-e-3.5-a15-20260211580868-official-FP6.zip
2

We should know if you use Windows or Linux? If you have Windows you might have a driver issue, check it in device-manager.

Then I must ask if you did install adb and fastboot? (For Windows and Linux relevant). For unlocking bootloader that is relevant. Please follow the installation guide from the part where you need to unlock bootloader

3

In my message, I have specified that I was using Ubuntu. I have installed the “platform tools” that contain adb and fastboot from flatpak. And of course, I precisely followed the instructions in the guide.

I am a bit puzzled about this forum. It tells me I have to wait half an hour before I can reply. Why?

4

I missed the Ubuntu part (very sorry bout that) and I was wondering what you installed. Not knowing how verse someone is with computers makes me imply lots…

So if you fastboot devices while in bootloader mode, what does it say?
Maybe usb port or cable aren’t good for proper connection.

Spam protection. You will gain badges, the more you are here and your rust level will also raise.

5

To stop the bootloop ideally you would try to regain Fastboot mode. You might try to time your button presses to get fastboot with the instant the phone is off. Worst case you can allow the battery to drain, recharge then boot to bootloader.

To beat the 30 rule you can probably continue to edit your last post.

6

$ fastboot devices
b70529f3 fastboot

Thanks for the clarification about the posting delay! Makes sense!

7

what about

fastboot --version

fastboot flashing get_unlock_ability

.

did you entered the unlock code
also did you confirm using the butons the button when unlock?
according to Install /e/OS on a Fairphone The Fairphone (Gen. 6) - “FP6” :

  • Get the unlock code from this site
  • Boot the device
  • Enable and connect Wifi
  • Enable Developer options
  • From developer options, enable USB debugging, allow OEM unlock
    and enter the code.
  • Reboot on fastboot by running the command in the PC console adb reboot bootloader, or with the device powered off - hold Volume Down + Power
  • unlock with fastboot flashing unlock
    Approve with volume + then power
    The device proceed with a factory reset, and automatically reboots
  • Reboot again into bootloader
  • Unlock critical with fastboot flashing unlock_critical
    Approve with volume + then power
8

Can you show the version of fastboot which is installed? In the past an old version (depends on the source where downloaded from) would result in failure.

9

My Ubuntu has version 34. But I already downloaded the last version and tried:

$ ./fastboot --version
fastboot version 36.0.0-13206524
Installed as /home/mtreichel/Downloads/platform-tools/fastboot
$ ./fastboot flashing unlock_critical
FAILED (remote: 'Flashing Unlock is not allowed
')
fastboot: error: Command failed

10

.

you must first

fastboot flashing unlock

and approve with volume + then power

.

what about ?

fastboot flashing get_unlock_ability
11

I did the “fastboot flashing unlock”, of course. “fastboot flashing get_unlock_ability” yields 0, so false. But I don’t know how to remedy that. The device is in a state that all is unlocked, except the critical partitions:

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

12

you may try to restore back FairphoneOS as a sane base.
(be carefull to SPL date), and retry /e/ later..
.
Search results for 'fastboot flashing get_unlock_ability order:latest' - /e/OS community
.
what if you relock and then run unlock_ability ?

13

That made it worse.

$ fastboot oem device-info
(bootloader) Verity mode: true
(bootloader) Device unlocked: false
(bootloader) Device critical unlocked: false
(bootloader) Charger screen enabled: true
OKAY [ 0.001s]
$ fastboot flashing get_unlock_ability
(bootloader) get_unlock_ability: 0
OKAY [ 0.001s]
Finished. Total time: 0.001s
$ fastboot flashing unlock
FAILED (remote: 'Flashing Unlock is not allowed
')
fastboot: error: Command failed

It does not even get to recovery mode anymore. At one point, it was telling me “The device is corrupt. It will not boot.”

I give up tor now.

14

That was unneeded as you had FairphoneOS android 15 based already installed,
and even strongly unrecommended on this forum when your intention is to install /e/.

  • upgrade to get the same android level regarding /e/ build YES,
  • but update to latest stockOS version including more recent android security patch than the /e/ build you plan to install NO,
    or else you have to let your bootloader unlocked until an /e/ build is released that match the android security patch date requirement (more recent than the one installed)

clearly explained here : (answered) Install /e/ on FP5 with newer Security Patches
also a warning is preset the Official Documentation (Caution)
according to Install /e/OS on a Fairphone The Fairphone (Gen. 6) - “FP6” :

Caution: The FP6 comes with an anti-rollback feature. Google Android anti-roll back feature is supposedly a way to ensure you are running the latest software version, including the latest security patches.

If you try installing a version of /e/OS based on a security patch that is older than the one on your device, you will brick your device. Click on Details below for detailed information

Détails

To check the security patch level on your phone with a locked bootloader, prior to installing /e/OS, open your phone Settings » About Phone » Android Version » Android Security Patch Level.Then compare it against the level of the security patch on the /e/OS build as visible in the Downloads for FP6 section below.

The following values control whether anti-rollback features are triggered on FP6:

  • Rollback protection errors trigger if you install an update whose version number is LESS than the rollback index’s value stored on device.
  • The value of rollback index is UPDATED to match ro.build.version.security_patch’s value of the currently installed version, but only if the bootloader is LOCKED.
  • The value of rollback index is NOT dependent on the currently installed ANDROID VERSION.
  • The value of rollback index can NEVER be DOWNGRADED.
  • Rollback protection errors are FATAL when the bootloader is LOCKED.
  • Rollback protection errors are IGNORED when the bootloader is UNLOCKED.

Here are some examples to help you understand how anti-rollback features work:

Example 1

  • Your FP6 with Google Android has a Security Patch Level saying June 5, 2025
  • The /e/OS build available says: /e/OS build : A15 official (Security patch: 2025-05-05)
  • In this example, the /e/OS build has an older Security Patch level than the origin, so the anti-roll back protection will trigger, and you will brick your phone
    Example 2
  • Your FP6 with Google Android has a Security Patch Level saying June 5, 2025.
  • The /e/OS build available says: /e/OS build : A15 official (Security patch: 2025-06-05)
  • In this example, the /e/OS build has the same Security Patch level than the origin, so the anti-roll back protection will pass, and you will be able to install /e/OS with no issues.

Example 3

  • Your FP6 runs Google A15 while /e/OS is now available based on A14.
  • Your FP6 with Google Android has a Security Patch Level saying 2025-10-03 or October 3rd, 2025.
  • The /e/OS build available says: /e/OS build : A15 official (Security patch: 2025-06-05)
  • In this example, the /e/OS build has an older Security Patch level than the origin, so the anti-roll back protection will trigger, even if the /e/OS version runs on a more recent version of AOSP. In this example, you will brick your phone.

.

.

it is the cause of your troubles !
there are no such warning in this F***ing web-installer

.

not entirely as you get Error: Critical partitions are still locked.

.

my bad…

.

15

to avoid such situation, i recently wrote this guide :

where it is hightlighted :

16

I am pretty sure that I followed the instructions à la lettre. Never mind! The device is bricked. Fairphone support told me I have to send it in.

17

That’s a rough spot to be in. On Fairphones this usually means the critical unlock is still blocked by OEM security, so only Fairphone support can re-authorize it or provide a recovery image. I’d contact them ASAP especially since the device is bootlooping and even stock Android won’t flash back.

18

Hello, was reading thread with interest, since I’m have similar topic.
My details:

FP6 (with security update 05.06.2025)

e/OS version 3.4 (Jan.2026)

PC-system: Linux

My current status:

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

fastboot flashing get_unlock_ability –>
(bootloader) get_unlock_ability: 0

Problem: When I try to flash it aborts because critical partitions are locked.

I got information from Co-Pilot that with FP6 there ar 2 levels and unlocking of critical is not possible:

>> Bootloader fastboot (classic red “FASTBOOT MODE” screen)

Userspace Fastboot (fastbootd) - needed for some Partitions

Therfeore I tried:

fastboot reboot fastboot
–>screen with 4 options
select:: enter recovery

→ brought new screen, with 11 options, but “fastbootd” is not shown
select::enter fastboot -->no change

select:: Apply Update from ADB
–>screen message: "now send package… with ADB sideloade

Action:: No reaction on power or up/down buttons – Disconnect USB cable – long press on Power button → screen message: “warning, previous installation failed, your device may fail to reboot…”,
Options: cancel / confirm

Action:: none option selected but a long press of Power + LowVol → restart of Android
(probabley wrong timing of my pressing)
Action:: long Power + LowVol press -->Now FP6 back in Fastboot screen

Question 1: not sure if I can run into a boot loop

Question 2: what to do next to get “unlock_critical” or fastbootd enabled?

Greatly appreciate your support!!

Carl-OS

19

Edit :

restore FairphoneOS How to manually install FairphoneOS on your Fairphone

  • NEVER relock the bootloader

  • Each time the phone reboot, re-enable Developer Options, USB debugging, and allow OEM

  • Always check fastboot oem device-info and fastboot flashing get_unlock_ability before and after any unlock command attempt

install /e/OS [HOWTO] a Clear Guide to install “IMG-e-builds” when /e/ web installer fails

  • Each time the phone reboot, re-enable Developer Options, USB debugging, and allow OEM

  • Always check fastboot oem device-info and fastboot flashing get_unlock_ability before and after any unlock command attempt

20

I had to send it in. Got it back with Android. I managed to reinstall /e/OS using the web installer. Locking the critical partitions was yet another issue that I eventually managed to overcome. All this was a pain in the neck. I finally got a phone that works more or less.