[Huawei P20 Lite Guides, News, & Discussion] TheWoodenPrince:
* Prelude

What started this journey was noticing that Tasker had restricted call screening

to android versions 10+. I would be delighted to hear what techniques fellow

forum members use to fight spam calls. I am a complete beginner, and so I

thought I would detail my journey in case it proves useful for others. There is

some outdated information and plenty of online tutorials, it just takes some

time to sort it out.

I have a Huawei P20 lite ANE LX3.

* Unlocking the Bootloader

I believe this is by far the most tedious step. Now that I am free from carrier

contracts, I know that my next phone will not be from a manufacturer with a

locked bootloader. In any case you may have some luck emailing Huawei directly

or through paid third-party services. What worked for me was potatoNV

GitHub - mashed-potatoes/PotatoNV: Unlock bootloader of Huawei devices on Kirin 960/95x/65x/620

Unlock bootloader of Huawei devices on Kirin 960/95x/65x/620 - mashed-potatoes/PotatoNV

github.com

The documentation on the repository is perfectly fine. Specifically in my case,

the device first showed under device manager as 'USP SER' and I had to reinstall

the test point drivers (found in the above README) for it to turn into 'Huawei

USB COM 1.0.' PotatoNV did its job and I managed to get my unlock code.

* Project Treble/GSI? Fastboot? ADB?

Again, being new to all of this, I did notice a lot of noise when searching

online for information. The most informative links I found useful:

- https://github.com/phhusson/treble_experimentations/wiki/Frequently-Asked-Questions-(FAQ)

- https://www.xda-developers.com/flash-generic-system-image-project-treble-device/

- https://developer.android.com/studio/releases/platform-tools

What is worth repeating is to USE THE GOOGLE PLAY APP 'TREBLE INFO' over the

more popular 'Treble Check', which falsely informed my that I needed an A image

rather than being fine with an A/B image. This wasted a lot of my time.

Initially I went down the route of using TWRP to flash the image, but this led

me to a soft brick (could very well be my own fault). The phone was frozen to

the TWRP splash screen, 'adb reboot bootloader' would not work. Power plus

volume down or volume up also had no effect. With no access to e-recovery or the

bootloader, I had really dug myself into a hole.

* Unscrewing a bricked phone

My last chance at fixing this consisted of getting the stock service firmware.

https://xdaforums.com/t/no-root-bootloader-lock-how-to-install-an-update-dload-method.3841557/

This forum thread was useful and on unscrewing the situation. The real useful

part of the above link was the 'Software Upgrade Guidelines' documentation.

So ultimately what unbricked my phone was following the direction to press all

three buttons (power, volume up, volume down) at once to enter "automatic

upgrade mode." I gather this was supposed to utilize the 'dload' folder I copied

over earlier. As an aside, it was a lifesaver that 'adb shell' gave me access to

some unix commands to make poking around easier. The automatic upgrade using the

'dload' folder failed.

BUT RESTARTING FROM THIS "AUTOMATIC UPGRADE MODE" GRANTED ME ACCESS TO RECOVERY

MODE VIA THE POWER BUTTON + VOLUME UP whereas before this was not the case. By

the grace of God this allowed me to download a recovery image from Huawei

servers. How much longer will their servers retain this image? I don't know, but

I'm grateful either way.

* Lineage OS successfully flashed

What instead worked for me was flashing the "GSI image without TWRP" - from the

2nd of the 3 links above. This is the image that I used:

lineage-19.0-20220211-UNOFFICIAL-treble_arm64_bgS-vndklite.img.xz

For sake of completeness M Rahman's 2018 article was still mostly accurate, the

'-u' flag may be omitted from 'fastboot -u flash system name_of_system.img'. The

only other thing I would append to his instructions is -AIF-'s recommendation to

4. Run command fastboot reboot, unplug your phone, when appears on screen yellow

warning, press and hold for 3 sec Volume Up . In eRecovery select 'Wipe

data/factory reset'.Reboot . - From:

https://xdaforums.com/t/losq-lir-lineageos-17-1-18-1-unofficial-gsi.4219291/

I say this because I had seen the power button + down volume/up volume technique

yield different results depending on whether the phone was connected to the

computer. I suspect this is the fault of HiSuite, but who is going to track down

a bug like this?

* Evaluation

Pros:

- I had solved my initial problem.

- The new phone feeling!

Cons:

The most noticeable deficiency was that adding an external SD card AS SYSTEM

STORAGE would never finish; I gave it about a day before giving up.

I will add further reports as they come up.

In conclusion I give props to Huawei for keeping that server image alive, but

last I heard they were pivoting away from smartphones into clean energy

altogether. If I were to do it all over again, I'm not sure it would be worth

it. This took a good day's worth of time.

Big thanks to the AOSP developers and the XDA community for buying

my old P20 lite a bit more time. I'm also interested in which companies the

community considers friendly to "popping the hood"/tweaker mentality.

Hope this was helpful for someone,