Fairphone - FP4 - FP4 - Documentation Suggestions

Caution: Ensure that you flash an image with a security patch level greater than the level of the existing security patch. Failure to do so will prevent you from locking your bootloader.”

"/e/OS build : R dev (Security patch: 2022-05-05)
/e/OS build : R stable (Security patch: 2022-05-05)"

What was the security patch level of Fairphone OS before you installed /e/OS?
If you were up-to-date, this would have been 2022-06-05 (July 11 release), one version before it was 2022-05-05 (May 30 release).

The upcoming /e/OS v1.2 would have 2022-06-05.

If the patch level is the reason for the issue, you would have to wait for /e/OS to raise its own patch level above the one which was there before /e/OS to then lock the bootloader. Here’s more … Locking Bootloader für FP4 after flashing e/os is not possible - #8 by AnotherElk … and more … Cannot re-lock bootloader on fairphone 4 - #3 by ff2u.

@Manoj: Perhaps it would be better to state “Failure to do so will prevent your device from booting successfully after locking your bootloader.” in the cautionary warning, since technically the locking itself doesn’t seem to get prevented.


Thanks for for your answer, clear and accurate.
I realize my message was inspired by frustration and that I had completely forgotten having updated the FP4 before proceeding.
My bad. Apologies.Being precised that the last time I flashed a phone was the whyred with the first beta of e/os!..
Having updated yesterday to e/os 1.2, the security patch would thus be at the same level, not above.
Should I wait further or may I proceed with the locking process?

The install document may not be the best place to show the patch level because the links take one to multiple choice of os versions to install!

It would be better to show patch level next to the os version on the download page if possible.


The documentation apparently was changed.
See Requirements - Caution - Details there, it now seems the same security patch level would be ok.

Let me check if it is possible to display the patch level on the download page.


Apparently, despite the current clear and detailed anti-rollback feature warning in the “Requirements” section users still fall into the trap bricking their device when locking the bootloader.

Can the warning be simply repeated at the start of the “Locking the Bootloader” section, when the possible damage is imminent?
And possibly at the start of the “Installing /e/” section, too, when the stock OS can still be booted to look up the security patch level?


Links to the details warning have been added before the Locking and Installing part of the guide.


A suggestion for the FP4 installation guide:

since many people struggle with getting into fastboot mode (including me), I would suggest 2 changes:

  1. change this:

Before install
How to Boot into bootloader mode
This section will be relevant later throughout the guide, when you need to reboot into bootloader mode.


Before install
How to Boot into bootloader mode, i.e. fastboot mode
This section will be relevant later throughout the guide, when you need to reboot into bootloader/fastboot mode.

  1. under “Unlocking the bootloader” i would add to step #5:

Alternatively, you can enter bootloader mode/fastboot mode by disconnecting the USB cable, turning off your Fairphone, then holding the volume down button and connecting the cable. (As in "Before install
How to boot into fastboot mode/reboot on fastboot) After a few seconds, your phone should display “FASTBOOT MODE”

This is also the treminology used on the fairphone website, where it is made very clear that the desired mode is called “fastboot mode” (which is also what the phone displays when in fastboot mode) and that there are 2 ways of getting there (https://support.fairphone.com/hc/en-us/articles/4405858258961-FP4-Manage-the-bootloader)
It would then be clear, too, that step #5 of “unlocking the bootloader” refers to the process mentioned in “Before install”. Then people can try the cable-button-push-tequnique if they struggle with adb commands, as many do.

Respectively, I would change all other mentions of “bootloader mode” to “fastboot mode” or at least add “fastboot mode” to them, to be coherent throughout the guide.

Installing /e/OS

  1. Boot your FP4 in bootloader mode, i.e. fastoot mode, and plug it to your computer

Locking the Bootloader

  1. Boot your device into bootloader, i.e. fastoot mode, if not already there, and plug it to your computer
  2. Reboot again your device into bootloader, i.e. fastoot mode, and plug it to your computer

I hope I could pinpoint the issue and that this change will help lots of people who are struggling with the adb-command.


I’m about to install /e/ on my FP4, and want to congratulate the authors of the tutorial for having done a good job of driving home the need to double-check everything.

However, I think the tutorial might benefit from more clarity in terms of structure.

Currently, the structure is the following:

  • Install /e/OS on a Fairphone FP4 - “FP4” (H1)
  • Requirements (H1)
    • Downloads for the FP4 (H2)
    • Before install (H2)
      • How to Boot into bootloader mode (H3)
    • Unlocking the bootloader (H2)
    • Installing /e/OS (H2)
      • Installing /e/OS using IMG or image file (H3)
    • Locking the Bootloader (H2)

This is confusing: I had to reread a few times to understand whether Unlocking the bootloader was something that I’m supposed to do prior to starting the installation process, or whether it is a process that I’ll be doing later in the tutorial in the same way as the How to Boot into bootloader mode explanation.

May I suggest to make the process more obvious by changing the structure to the one below, adding section numbers, and adding a table of contents on top?

  • Install /e/OS on a Fairphone FP4 - “FP4” (H1)
    • 0. Requirements (H2)
      • Downloads for the FP4 (H3)
      • Before install (H3)
        • How to Boot into bootloader mode (H4)
    • 1. Unlocking the bootloader (H2)
    • 2. Installing /e/OS (H2)
      • Installing /e/OS using IMG or image file (H3)
    • 3. Locking the Bootloader (H2)

And a few minor suggestions:

  • The tutorial mentions a Volume Down button and a volume + one: it should be either down and up, or - and +.
  • This has been mentioned before, but saying All the console commands are run [...] in the adb console. is confusing, as the commands are run in a normal console/command line, not in an adb-specific shell, if I understand correctly.
  • @moraene’s clarification on bootloader mode = fastboot mode is definitely helpful

Thanks, and please let me know if my understanding of the installation process is wrong.


Hi, I just got my new Fairphone 4 and did the mistake of upgrading the stock Android first. So now I have to wait for patch level 2202-08-05 before I can install without bricking. If I understand this correctly, e-1.4 would contain this patch level. The instructions page says both “dev” and “stable” are on “Security patch: 2022-07-05”, while looking at the links it looks like “dev” already contains the e-1.4.

Now my questions:

  • Is it save for me to install “e-1.4 dev” version?
  • What benefit do I have from waiting for “stable” and how long does that usually take until it will appear on the download page?

Thanks for answers!

So, the stable branch also got updated to e-1.4. So I took the risk and it worked out. Perhaps update the install page to reflect the new security patch level?

I’m not very tech savvy but I do care about my privacy and I would love to opt out of androidOS. I’m stuck on this guide though, and I’m sure I’m being a noob, but hopefully someone can help me out.

So I just bought a FP4 with Android pre-installed. I want to switch to /e/os (or LineageOS4MG, but it seems that’s not possible (yet)?). So I follow the guide and I read the warning that talks about the anti-rollback feature. So I look up my android security patch which is: September 05, 2022. So which file should I download? Do I need R dev or R stable? On this website ( Different Build Types ) it says that the stables are only available for Murena? But at the dev page ( /e/ image ROM download ) there is not a file that has the same date as my security patch. So then what do I do?

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Stable version can be found here as mentioned in the installation docs:
After the installation you just should not relock the bootloader as the anti-rollback would make your device unbootable (currently the FPOS patch level is higher than /e/OS patch level). Having OEM unlock disabled at that moment would even brick your device.


Hi Bjoern, I’m having similar problem to yours and need to ask if you locked your bootloader after the installation?

my FP4 now is booting with /e/OS!
thanks e-foundation and all of you on this forum for your valuable tips! i couldn’t have done this without you.

couple of points:

  1. i installed adb and fastboot from the link provided in the guide. thats important to use to ensure the latest version.
  2. for whatever reason could not get PATH to adb/fastboot when updating my.bashrc file so ran all the required commands from the dir where i installed the tools.
  3. locking the crtical partition and bootloader i did after i installed all my apps etc on my phone.appears that it reset everything to default /e/OS settings so i needed to the apps installs again.so best to lock before you personalize.
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From Ancient Greek κῦδος (kûdos, “praise, renown”).

Hi! I just got a new (stock) Fairphone 4 and would like to try /e/OS before I start migrating data from my old phone. Hence I’m less worried about losing data for now, and I could easily roll back to stock OS if necessary.

I’m following the guide at Install /e/OS on a Fairphone FP4 - “FP4” which is pretty clear.

But I’m a bit worried about the “security patch level” and do not want to brick my device. There doesn’t seem to be any up-to-date information about the patch level in the /e/OS factory image (the page says 2022-08-05 which I don’t think is correct).

However I found that I can grab the patch level from the image file simply by running (on Linux)

$ strings super.img | grep 'ro.build.version.security_patch='

which gives me 2022-10-05 for the 1.51 image (dev release).

Can someone confirm if that’s actually the patch level that I need to compare with the version installed on my phone to avoid bricking?

Also, if I understand this thread correctly, my phone wouldn’t brick itself even if I install an older patch level, as long as I don’t relock the bootloader after installation. Is this correct?

EDIT: There’s also ro.vendor.build.security_patch=2022-09-05 in the same image file. In addition I found that Releases · e / os / releases · GitLab also lists 2022-09-01 as patch level for the v1.5 so that is probably the one I need. (But then why does the image file show higher/different patch levels than the releases page?)

I install /e/OS to my FP4 a few days ago. The actually security patch level you can see on the screenshots from my actually installed FP4 in this thread.

I hope i can help you.

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Thank you @confu!

I was also able to install /e/OS on my new phone without any issues. I think the most “official” way of getting the patch level is indeed the releases list on GitLab, but the documentation on the install guide needs to be updated.

For now I switched back to stock Android because I wanted to test and compare the camera apps. It is really unfortunate that the wide angle camera is not supported yet in /e/OS (or is it?) Maybe this should be mentioned somewhere too? Info about Fairphone FP4 - FP4 does not say anything about this limitation.

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Maybe I’m over seeing something, but I haven’t been able to get a wide angle shot yet. That will be a big drawback for some, I rather value a good cloud connection. I only snap the occasional picture, but nothing you would award a prize for. Nevertheless, I think that the camera implementation (Open Camera) is far behind the possibilities of the hardware. Maybe comes in one of the next updates times a revision of the APP with support for multi-lens and wide-angle cameras.