Fastboot mode not available

I’ve reverted FP4 to Android which installed fine. I’ve follow Faiphone official instructions, all good with installation. The problem occurred when I locked the bootloader.
Once I pressed power key to lock the bootloader the phone booted fine, but when I needed to reboot I’ve find out that at the boot prompt there’s the following message: “Bootloader unlocked and software integrity cannot be guaranteed.”

I understand the meaning, but I though I had locked the bootloader?

The problem that I’m having is no fastboot mode available when I press POWER and VOLUME DOWN keys.

Screenshot 2023-01-28 at 16-35-23 FP4. Install Fairphone OS offline

Not sure where the Screenshot is coming from but official instructions to boot into bootloader are different please read here

However I would not advise to lock the bootloader ,the chance you have a brick afterwards is quite high

Please search for “trapped in fastboot mode…”

Thanks for support.

The screnshot is from Fairphone website and they do mention locking the bootloader, I was follow those instructions.

The link that you posted which mentions also the same steps which I’ve followed.

This is what is to be done for the FP4, copied from “my” link

Put your Fairphone in fastboot mode. You can do so in one of the following ways:

  1. If you have installed the command-line tool ADB.
  2. Start a Command Prompt (Windows) or a terminal (macOS/Linux).
  3. Use a USB data cable to connect your FP4 to a computer via a USB cable.
  4. Type ADB reboot bootloader and press the Enter :leftwards_arrow_with_hook: key.
  5. Alternatively, you can disconnect the USB cable, turn off your Fairphone, then connect the cable and hold the volume down button. After a few seconds, you’ll see the fastboot mode.

I´m very sorry to say that but that really sounds as you´ve bricked your phone. Have a look here:

You may be lucky if OEM unlock is still enabled. But when going back to FPOS I doubt it… Good news is that because you´ve flashed FPOS successfully your device is probably covered by warranty…

It it was this message than I dont think the phone is bricked than the bootloader is just unlocked

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Yes, you’re right. I’d misread the message. That’s very good in this case… :wink:

Thanks man,

Developer options > OEM unlocking (Bootloader is already unlocked)

What do you suggest?

Developer options > OEM unlocking (Bootloader is already unlocked)

Yes, bootloader is unlocked. So locking your bootloader did not work. But maybe that’s good - at least until it’s clear if OEM unlocking is enabled.
The setting Developer options > OEM unlocking is probably greyed out. But it’s the slider on the right or on the left side?

Thank’s Volker, yep the OEM unlocking is greyed out and the slider all the way to the left

Any thoughts?
Should I send it to fairphone?
Does anyone now the steps, please shine a light?


Well, that’s actually as expected (as your bootloader is unlocked and you’ve installed FPOS).
BUT it means that if you now lock your bootloader and something goes wrong your phone will be bricked (as you won’t be able to unlock it again without booting it successfully). So my recommendation would be to not relock it…

No, why should you? It’s all working fine, isn’t it? Or did I miss the exact problem you’re having (if you have one, can you please rephrase it)?


No you didn’t miss the point, I’ve missed the point my self

I’m planning to sell it , is it alright to do so?


You could do the update which was released just days ago. After that I’d expect that relocking the bootloader should succeed (but still no guarantee - relocking the bootloader might still brick the device…).

Or you just inform a possible buyer that the bootloader is unlocked.

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