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?
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
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?
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.
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.
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.
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:
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)
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.
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it is the cause of your troubles !
there are no such warning in this F***ing web-installer
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not entirely as you get Error: Critical partitions are still locked.