Help P20 Pro CLT-L29 bricked after downgrade firmware

nxjeff

Junior Member
Jul 21, 2021
2
0
Malaysia
The whole journey was started because I wanted to root my phone to use some feature that must be rooted, I was on CLT-L29 9.1.0.388(C636E3R1P13) latest firmware available on this phone.

I spent sometime to read and discover there is no way for this phone to be unlocked (bootloader) without using test point mode, therefore, I disassembled the phone, and learnt how to do test point. everything is smooth.
Naive me thought that I am at testpoint mode right now I can just use HCU tool to unlock the bootloader directly, therefore I purchased HCU Tool Time Licensed 3 days from MartView (the sale representative is friendly and nice, very responsive!), so I just login and follow exactly the steps I found on youtube, selected Kirim970, there are several bootloaders for this processor, so I tried each of them with the "READ PHONE" button, only 1 is not giving error, so I used that (Kirin970_T2_A8.1_V5),

modify the bootloader lock -> change to UNLOCKED (this is my main purpose).

leave the rest to default, and click on repair,


2021-07-21 13:17:29.787 Repairing...
2021-07-21 13:17:29.801 Write FB User lock not supported for this model, skipped!
2021-07-21 13:17:29.816 Write partition oeminfo...
2021-07-21 13:17:32.263 Write partition oeminfo success!
2021-07-21 13:17:32.292 Unlocking restrictions...
2021-07-21 13:17:32.330 Unlock restrictions success!
2021-07-21 13:17:32.341 Rebooting...
2021-07-21 13:17:32.388 Reboot success!
2021-07-21 13:17:32.401 Done!

After few restart I still don't get the bootloader unlocked, then i realised there is a "2021-07-21 13:17:29.801 Write FB User lock not supported for this model, skipped!", which mean it actually failed at that point.
So I keep digging around, assume that I must downgrade to firmware that is 8.1 in order for this bootloader write works.
Therefore, I plug it into HiSuite, the oldest I can go is still 9.0, and what I understand is Hi Suite will go back one or two versions, if I were to downgrade using it, I have to downgrade few more times, but my internet is metered ;) therefore, I cancel the downgrade.
And found out there is a way to cheat the HiSuite, using HiSuite Proxy, great, I was greedy, I straight away proxified the latest version as 8.1.0.0xx. Surprisingly HiSuite took it and allow me to download!
Everything looks great, ..10%.. 50%.. 80%.. the phone start to go into upgrading mode, then all of sudden, installation failed, unable to upgrade, two button was shown, Go to eRecovery, Reboot to system.
At this point I just click on eRecovery, right after that, the screen never go out of black screen, not even Huawei logo is shown.

The phone is still accessible, because when i plug into the pc, fastboot driver is shown, but only fastboot.

here is the latest info that fastboot can fetch:
Model: CLT-L29
Firmware: CLT-L29 9.0.0.168(C636E2R1P12)
Rescue: rescue:Chipset-boston 8.1.0.001(01RZ)
Vendor: hw
Country: spcseas
Version limitation: ON
SIMCARDMODE: double
Bootloader User lock: locked

What I have tried:
1. I tried to download board software (Charlotte-L29C_8.1.0.158(C636)_Firmware_8.1.0_r1_EMUI8.1_05015AQX) from the dc-phoenix app repo, flash update using dc-phoenix, does not work.
2 I tried to download the original firmware my phone have before this journey, CLT-L29 9.1.0.388(C636E3R1P13T8)_Firmware_EMUI9.1.0_05015AQX from paid GSMfirmsweb, still no luck

both ends with
Software written
7/21/2021 9:15:03 PM Writing device finished OK
Extracting recovery partition

Extracting partition: ERECOVERY_KERNEL

Extracting partition: ERECOVERY_VENDOR

Extracting partition: ERECOVERY_RAMDISK
Recovery partition not found

Attached full log.

I am really out of help, what I want is just to unlock the booloader, now I just want my phone to be back ;)

Please help me, I will be here waiting here, let me know I will show anything you would want to know.


I have left 2 days of license I hope I can get back the phone before the license end.
 

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klode82

Junior Member
Dec 28, 2021
1
0
Milano
Please. can you explain what do you have done? I have the same issue. But now I'm stuck with bootloader locked. Thanks for your supply!
 
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