EFIDroid (multiboot) for the Fairphone 2

System partition “is” unticked in TWRP and I can’t modify that. I can only thick “Mount system partition read-only”. I tried and I got several “Fail to unmount ‘/system’ (Invalid argument)” messages. I format dalvik and system cache but when I try to boot into Open OS I see Fairphone logo, then back again in EfiDroid.
Another thing, now I can’t power off my FP2, only reboot.
@paulakreuzer There is no prompt asking for permissions at all.

Uhm… I am out of ideas unfortunately…

I don’t know if this prompt is related to your issue, but if it is try rebooting from within TWRP, that usually triggers the prompt if you haven’t seen it yet.

@z3ntu and @paulakreuzer Thank you for your help!

Did you solve your issue?

Sorry, I say “yes”, because I think we can’t do much more for now :slight_smile:

So I just tried again and if you get that system error, unmount the partition, format it, try to mount it, that should work, unmount it again and flash the zip. I tried it with FP Open 16.12 and it worked fine.

@paulakreuzer Why can’t I edit my original post anymore?

Also general: I tried flashing FP2-gms72-1.11.1-ota.zip but I just get a forced reboot (last_kmsg is corrupted as always)… FP Open 16.12 is confirmed to (at least) boot.

I wikified it so that you can edit it.


Hello! Can I safely format /system partition without losing data in FPOS

If you chose a secondary rom when booting into TWRP, yes. Otherwise, no (then you will format the primary roms system partition).

Thank you, I will try this evening.

1 Like

Hello. I tried two times. First time no change, but I can power off the
phone again. Second time I format system, cache and dalvik: no more
warning during zip install! But no more boot in Open OS…
Back again to job: thank you a lot, have a good day!

@z3ntu do you think it could be possible to add an option to boot to the charging animation?

The biggest problem I have with EFIDroid is that when my battery is deep-discharged it’s a hassle to load it again. When I plug in the dead phone EFIDroid starts automatically and it stays fully lit all the time without showing a battery percentage (the LED doesn’t light either).

Now when I try to boot to early it just gets stuck, so the best workaround I got so far is: Wait about 10 minutes and then boot to FP OS’s TWRP (I have the feeling it boots faster than Open OS’s TWRP - does that make any sense?). There I can see the battery percentage & LED and the screen goes black after some time so charging is much faster.


I wanted to try FP Open and followed the instructions in https://z3ntu.github.io/2016/11/01/Install-and-configure-efidroid.html

However when I reboot into EFIDroid I have no TWRP entry under the “Recovery” category, instead there is “Recovery (internal)”.

Do I need to install TWRP before installing EFIDroid?

Regards, pesche

TWRP would be better but the stock recovery should work too theoretically (never tested it with it though)

With the stock recovery EFIDroid selecting “Recovery” just boots into EFIDroid again.

So I tried to install TWRP 3.0.2 from the ✏ Porting TWRP recovery thread, but couldn’t get it to be flashed permanently (even with the Volume Up Button: TWRP is shown, but after I reboot it has vanished again).

Do I need to unistall EFIDroid to install TWRP permanently?

Answering myself… After powering off EFIDroid showed the TWRP recovery, so this worked.

When installing the FP Open 16.12 image however there was a red Failed to mount '/system' error message and trying to boot into FP Open just lands in EFIDroid again.

From TWRP: Unmount /system, format /system and finally unmount all partitions and then install the zip.

Thanks, z3ntu. However I just made a backup with TWRP and installed FP Open OS without EFIDroid. I hope I don’t need FP OS anymore.