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.
Type ADB reboot bootloader and press the Enter key.
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…
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?
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)?
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.