Can't downgrade EMUI from 9.1.0 to 8.0.0

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-Alf-

Senior Member
fastboot oem get-build-number
Code:
(bootloader) :LLD-L31 9.1.0.149(C432E6R1P4)

fastboot oem get-product-model

Code:
 (bootloader) LLD-L31

fastboot getvar vendorcountry
Code:
vendorcountry: hw/eu

fastboot oem oeminforead-CUSTOM_VERSION


Code:
 (bootloader) :LLD-L31-CUST 9.1.0.8(C432)

fastboot oem oeminforead-SYSTEM_VERSION
Code:
(bootloader) :LLD-L31 9.1.0.117(C432E4R1P3)
Maybe I need to install something on the LLD-L31
No need to install anything.
 

TabbyChii

Member
Jan 11, 2023
23
0
Did I mess up anything then?
HiSuite does not recognise the phone on any computer, I can't force install any of the previous EMUI firmware (software installation failed).
 

TabbyChii

Member
Jan 11, 2023
23
0
Formated my laptop and installed Windows 10 on it.
Now the issue is that I can't manage to do anything with the test point.

I tried to do the short circuiting with a tweezer, a stable a pair of screw driver, a scissor, there is no "USB SER" or "HUAWEI USB COM 1.0" showing up. I only get "Android Sooner SIngle ADB interface"
 
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TabbyChii

Member
Jan 11, 2023
23
0
1. You can downgrade to Oreo via HiSuite. If the rollback option is not available with your HiSuite ("switch to the older version" or "Earlier version"), you must downgrade to the lower (first) 9.1.0 build version number doing the dload method (flashing Service ROM ) and try again with HiSuite. sometimes better results are with the Chinese version:
Link
2. A) using HCU-client or DC-unlocker (you have downgrade to Oreo build number with google patch april-june 2018 via dload method)
B) for free (that can be done on 9.1.0 ) using potatonv method, Guide

in both cases, you will get an BL unlock code.
How to unlock:
- In Developer options in your phone enable OEM unlock option (with this setting you will get "FRP unlock" status in fastboot mode, it's very important).
- Connect your phone in fastboot mode to the PC and run command
fastboot oem unlock xxxxYour_Codexxx
fastboot reboot

3) Download TWRP
Link
- in fastboot mode run command
fastboot flash recovery_ramdisk xxTWRP'sNamexx.img
(e.g. fastboot flash recovery_ramdisk TWRP-9.1.img)
fastboot reboot
Done.
It worked, it really took me a while to understand that I needed to boot the phone while holding volume down+power, and then plugging the cable.

edited : https://forum.xda-developers.com/t/rom-unofficial-leland-8-1-lineageos-15-1.3780962/I grabbed this with ARM64 8.1 nano. I after instaling the files, I can't access LineageOS, but almost there. I also upgraded back to 9.1.0.if I install this https://mega.nz/#!tkcTlATI!A8UJGPBGtxJbLcUOJoxCGJj5PFZXzCnjbb3OkwqKTP8, I can't interact on anything. I wentt with https://mega.nz/#!B8kWgJDC!_hj7xkTzF9Uj66wKjtrWPHEV5Dbkk7Q256tuiKg7FQU
 
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TabbyChii

Member
Jan 11, 2023
23
0

TabbyChii

Member
Jan 11, 2023
23
0
Try to unlock bootloader again.
It is still unlocked if I check the fastboot menu

Code:
PHONE unlocked
FRP Unlock
Worse can I can try that 15.1 rom, but I will ned to downgrade again.

And with all that fiddlig with my laptop, I kind of broke windows.
SHould be easy fixable tho.
 
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TabbyChii

Member
Jan 11, 2023
23
0
LineageOS 18.1 Unofficial (e.g. Lir-v316) works normally on LLD-L31, maybe you are doing something wrong.
I can try again, though, are the GAPPS included.... nevermid I can just delve them out myself
As for Lineage 15.1, it did nto works.

EDIT : state of affaird, after each failed install, I have to go through this tutorial https://forum.xda-developers.com/t/what-to-do-with-a-fully-cleansed-phone.4414515/post-86564803 but this time I can't get into eRecovery anymore by pressing both volume button and the power button. Issue I only boot into TWRP and nothing else.
 
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TabbyChii

Member
Jan 11, 2023
23
0
I need ot reflash EMUI 9.1 first, right.
BTW, do I still need HiSuite?

EDIT:
Gonna descripbe what I am doing step by step.
-Boot into fastboot
-fastboot erase system
- fastboot erase recovery_ramdisk
- fastboot flash recovery_ramdisk [TWRP]
- reboot fastboot
- hold volume up + powerbutton
- wipe data (failed)
- install TWRP into eRecovery
- install recovery 9.1 into Recovery
- pwoer off
- power on while holding both volume buttons.
-stuck on "your device is booting now..."
- TWRP keep saying "noOS installed" after flashing anything.

Also, no success by using TWRP tool for restauring the stock recovery anderecovery tools.
 
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-Alf-

Senior Member
what I am doing step by step.
-Boot into fastboot
-fastboot erase system
- fastboot erase recovery_ramdisk
- fastboot flash recovery_ramdisk [TWRP]
- reboot fastboot
- hold volume up + powerbutton
- wipe data (failed)
- install TWRP into eRecovery
- install recovery 9.1 into Recovery
- pwoer off
- power on while holding both volume buttons.
-stuck on "your device is booting now...
Is this some new know-how? :)
I don't know where you got these procedures from, but it looks like you don't know what you're doing. First you erase the system, and then you are surprised that you do not have an OS installed?
Install the stock Recovery via fastboot and then the Service ROM via the dload method. Before it's too late...
 

TabbyChii

Member
Jan 11, 2023
23
0
Is this some new know-how? :)
I don't know where you got these procedures from, but it looks like you don't know what you're doing. First you erase the system, and then you are surprised that you do not have an OS installed?
Install the stock Recovery via fastboot and then the Service ROM via the dload method. Before it's too late...
From here, though, i may have missed context.
Shouldn't deal with phones past 4am
 

TabbyChii

Member
Jan 11, 2023
23
0
Is this some new know-how? :)
I don't know where you got these procedures from, but it looks like you don't know what you're doing. First you erase the system, and then you are surprised that you do not have an OS installed?
Install the stock Recovery via fastboot and then the Service ROM via the dload method. Before it's too late...
I am less tired.
If I remember right, it is :
- enter fastboot
- fastboot flash recovery_ramdisk [stock recovery].img
- shutdown
- power button+volume up
- boot into recovery?

I am at "your device is booting now..."

Will fastboot again.

Just in case, is there a way to flash eRecovery? Nevermind, found it.

Still stuck at your device is booting now.
 
Last edited:

TabbyChii

Member
Jan 11, 2023
23
0
Is this some new know-how? :)
I don't know where you got these procedures from, but it looks like you don't know what you're doing. First you erase the system, and then you are surprised that you do not have an OS installed?
Install the stock Recovery via fastboot and then the Service ROM via the dload method. Before it's too late...
Just to make sure the system partition I deleleted, was it the android system, or something else?
 

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