Locking bootloader after calyxos installed

Hi all

I managed to install calyxos on my fairphone 4 but i am not able to lock the bootloader. if i do so, i cant boot the phone. it says my device is corrupt. in case i leave the bootloader unlocked, everythings fine. i wonder what i do wrong? any help is much appreciated.

Did you use the installation tool for the install?

Yes absolutely. I followed the step by step manual on the calyxos website. The last step was telling me to lock the boltloader on my phone, which I did. But im not able to boot the phone then. If I ignore this last step, leaving the boltloader unlocked, everything is fine. I would really like to lock the bootloader though…

I think you’re better off asking for help at an official CalyxOS forum, like on their Reddit. Maybe the devs know what’s up.

If you updated your phone to the latest FPOS release (175) before installing CalyxOS, that could cause issues since the patch level of the factory images linked in the instructions is lower.
Try the newer 4.4.1 factory images, those should have the right patch level.

Whatever you do, don’t manually lock the bootloader!

The Matrix channel is the best place to ask for help, there’s usually someone around who knows what to do.


Thank you so much guys for helping me. I know its hard to deal with noobs like me, so forgive me the following question (I just really dont want to brick my phone): What do you mean with manually locking the bootloader? Im a little scared, because the last step of the manual (on the calyxos website) tells me to lock it. So if I replace the factory image i used with the one you linked me hirnsushi, should I be safe? I would follow the same steps as stated in the manual, just using the newer factory image.

I wish you all a happy new year :slight_smile:

Oh and yes, I did update to the latest FPOS - your right. Would explaine my little dificulties im facing right now becuase of the missmatch of the versions… Thank you all in advance

As long as you use the Calyx installer, which has safeguards in place that should hopefully keep you from bricking (and since you where able to unlock the bootloader again, those seem to work just fine), you should generally be safe :crossed_fingers:

It becomes dangerous if you don’t lock it at the end of the installation, boot into the system and then issue the command to lock the bootloader manually after that. Never do that.

In short, use the device flasher, and if something doesn’t work just run it again, don’t run any other commands.

Exactly :slightly_smiling_face:

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HOOOLLLYYYYY SMOOOOKES :smiley: Im so happy it worked. Thank you so much. Happy new year :slight_smile:


Hello,I hope I am in the right place for my problem. I followed the procedure to install CalyxOs on FP4 using the dedicated installer. After launching the installer and validating the unlocking of the bootloader twice (5 and 5.1 procedure) the phone rebooted and it doesn’t turn on anymore no matter what I do. Anyone have an idea what I can do?

Welcome to the community :wave:

When you say doesn’t turn on, do you mean the screen stays black regardless of what you are doing? :thinking:

Could you check the following please :pray:

  • When connected to a PC, do you get any output for fastboot devices?
  • What happens if you disconnect it and press Power for 10+ seconds?
  • Does anything happen if you connect it to a charger and wait for some time?

Hello, thanks for the answer.

Yes I tried holding 10sec, 15 sec, removed battery for a day and tried again but nothing turns the screen on. The phone doesn’t seem to boot at all.

When I connect the phone to my PC and do fastboot devices there is no output whatsoever.
When I disconnect and press for +10 seconds “nothing” happens. At least nothing that I can see, no led, no vibration, black screen.
When I connect it to a charger nothing happens, I will try to leave it longer.

So after poking around for a bit I have some news and it’s not so great…

The phone is doing “something” when I hold the power button for +10 seconds so I tried to find what.
So I plugged it into the PC and without trying to turn it on I looked to see if my phone was detected. And it is as you can see:

But after some research, I found that this QUSB_BULK_CID error happens when the phone is bricked (suspected that) and the phone enter a EDL mode when I try to power it up. Now, I don’t think I can get out of this situation without sending it to Fairphone (but I’m all ears) so I would like to know how I ended up in this situation…

Usually you should be able to leave EDL mode by unplugging and holding Power + either Vol. up or Vol. down, IIRC … :thinking:

If that doesn’t work you might be dealing with some kind of hardware failure, as you already suspected :grimacing:
You might be able to collect some additional information with edl, but we are lacking the necessary loader to actually do / fix something in that mode.


Hello again,

I sent my phone to do the repair and here’s the answer:

“In the order of analysis, the technician always starts with the possible software repair. Without success, the technician indicates that it is impossible to push the stable software version into the device. So the technician cross-tests the components of the device. In your case, the motherboard.”

Has this ever happened to anyone (in your experience)?
How is it possible to “destroy” the motherboard when installing a custom OS (calyx os)?
I can’t change the motherboard so what could be my options ?
Is it the right place to ask these questions ?

Thanks in advance?

Can’t say I have seen a case exactly like yours before, countless bricks, sure, but not a phone stuck in EDL.

If you haven’t already talk to Fairphone support again and let them handle it, this looks like a hardware failure that should absolutely be covered by warranty.
Cordon can be annoying to communicate with, in the beginning when people started bricking they offered to “fix” peoples phones by sending them a new one at full price …


When I understand your previous post correctly the only you did was unlocking the bootloader, you never got behind that step and never flashed CalyxOS? If so I would concentrate on this, because when you state you flashed another System they will most likely argue its not under warranty


To conclude with my problem. After talking to fairphone and cordon for a month, they (cordon) concluded that the calyx os install was the source of the problem (without further explanation) and that flashing the phone was impossible (PCB replacement).

Fairphone support

Thank you for your help.


Without a more detailed description I don’t find Cordons explanation very convincing…

How much did you have to pay to get it fixed?


I didn’t find them very convincing either. I couldn’t really exchange with Cordon so I had to go through Fairphone support. I repeatedly asked for more information (e.g why the edl loaders didn’t work) but I couldn’t get an answer except for “we’re trusting Cordon’s expertise”.

Fairphone support

In the end, I had to pay for the PCBA change, which cost me about 300 euros (220 for the PCB and 20% TVA).

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