[Huawei P10 Questions & Answers] rlees85:
Since this Huawei P10 never received a single OTA update (from Carphone Warehouse, SIM free) and was stuck on Nougat I decided to go custom ROM route. This was a HUGE mistake but I did learn a lot which may be helpful to others.

The situation goes like this:

Tried to flash TWRP, failed, tried to flash system (openkirin pie) also failed. Nothing would work at all.

Tried to re-lock bootloader thinking it would make everything stock again automagically (not sure why I thought it does on some devices).

Then got into bootloop with no access to fastboot as bootloader HAD to force factory reset but couldn't (broken recovery). After some time you'd get some white EMUI screen in Chinese where all the options are broken.

Flashed the latest version I could find using DC-Phoenix with flashpoint, this is where I really ****ed up as this firmware had XLOADER2.

Phone is alive!!!! but no IMEI and NCK lock. HCU tool, DC unlocker, etc, nothing works with XLOADER2 for fixing the IMEI or NCK lock.

Tried to downgrade to Nougat. Complete brick, back into testpoint mode.....

Testpoint mode cannot even flash XLOADER1 anymore!! I did still manage to get the phone working again, but now it is a tablet :(.

So in short:

YOU STILL CANNOT GO BACK TO XLOADER1 FROM XLOADER2 - EVEN if you disassemble and use testpoint mode! I have NO idea what Huawei have done to prevent this but its something evil. So if you are at this point with no IMEI then you will never have a working phone ever again. Tablet yes if you are lucky but NOT phone.

So the process (not detailed, requires Google) to make your bricked XLOADER2 Huawei P10 a tablet rather than a brick:

You'll need DC-phoenix and maybe a 3-day 15 credit license but don't by the license until it tells you to otherwise it might be a waste of money if you have problems with disassembly for example

Download HiSuite to make sure you have all the required drivers

Disassemble your phone, plug USB into the computer, ground the testpoint pin and hold the power button

You should see a HUAWEI USB COM device in device manager

Using DC phoenix you need to select a booloader mode, try all Kirin 960 bootloaders until one works. You can also select an OEMINFO update at this point too if you want

Your phone is now in some half working fastboot mode. Leave it plugged in!

Using firmware finder, find the "379" firmware (the latest one they have for VTR-Lx9) where x is 0 or 2.

Using firmware extrator, extract: xloader, fastboot, teeos, ptable (hisi_gpt or something like that), vbmeta, kernel (ramdisk)

Using fastboot manually flash all of these images, kernel may fail but its OK if it does

Now fastboot reboot, your phone will brick again. Put it back into testpoint mode

Using DC-phoenix to select a bootloader (again) use the same Kirin 960 one as what worked for you before

Use DC phoenix to flash the "379" firmware and customisation and run the update.

If ANY steps fail, repeat again to fastboot reboot, testpoint mode, bootloader from DC phoenix, then run the update.

If all partitions flash OK and it asks you to go into update mode, with the USB connected, hold vol-, vol+ and power until 3 seconds AFTER you feel the phone vibrate

Eventually you should see some more COM ports appear in device manager (PCUI and some other random one). If you can see your screen (doubtful as it will be face down) you will see update mode 5%

Again, update with DC-phoenix (same 379 firmware and customisation you did before)

Your brick should now be a tablet. Bootloader should be unlocked if it was unlocked at the start of the process.

So typing that out and given I don't have time or the load of files I had downloaded to do this there is not much detail so if you do this you need to be someone who knows what they are doing really. I don't expect anyone to actually be stupid enough to follow this.

I just don't understand what XLOADER2 did (must be at a very low hardware/bios level) so completely lock the device down even in testpoint mode. I'd imagine even their repair centres would not be possible to repair IMEI now and just throw motherboard into the bin.