[Mate 8 General] Samavb:
Huawei Mate 8 - L29C636B585 - bootloader & phone problem - Fix

Hi,

Don't worry I will do my best to help you. Please read everything below carefully.

Even though you know let me make few things clear

Erecovery

This is a recovery mode that is useful only when you have stock recovery & stock rom installed.

You can update to latest firmware through wifi connection from Huawei servers.

To go into this mode

1) Switch off the phone

2) Press and hold volume up button & power button

with phone is connected to charger or laptop

But if you have TWRP or bootloader unlocked this will not work.

Recovery mode

This is normal recovery mode

If you have stock ROM & stock recovery then you will get options to Wipe data /factory reset & wipe cache partition

If you TWRP or unlocked bootloader then this recovery will not work

In order to go into this mode

1) Switch off the phone

2) Press & hold volume up & power button together

WITHOUT connecting to charger or laptop

If you have TWRP installed then it will give you TWRP or else stock recovery - but key combination is same for both. You can only have 1 recovery at any time.

This is the difference between Erecovery & Recovery mode

Fastboot mode

This is a very important mode which is very useful to unbrick Huawei mate phones.

To go into this mode

1) Switch off the phone

2) Press & hold volume down and then connect it to laptop or computer (not charger, because there is no use if you do that)

You will have white screen & it will show you FRP status & phone locked or unlocked status

This is where you found about FRP locked. But this will not come unless you enter

I explained all these modes because you will be using them to troubleshoot & dont want you to get confused with terminology. It saves time.

When you boot your phone, if the bootloader is unlocked you will see some text on your phone screen & then it will move forward to Huawei logo & into OS. This is normal. But if you are facing any other issues - like bootloop or phone not working properly or if it is giving some other error then you have to fix them.

First, you need to get the stock ROM L29C636B585. Try to search in other threads for Huawei Mate 8, you should be get 2 zip files.

Extract both the zip files to a folder. You will have 2 update.app files in separate folders. 1st is update.zip

Yes even though you have that firmware on your phone, if you want to properly unlock the bootloader you have to first get Stock ROM with stock recovery only then you can unlock bootloader safely.

Get the Huawei update extractor software - > HuaweiUpdateExtractor_0.9.9.3

Extract the software to a folder

Go to that folder

Double click on HuaweiUpdateExtractor - red color application icon

Browse to the folder where you have the update.app extracted from update.zip

Check if you can find recovery.img, system.img & boot.img

Extract them to a folder using this software

If you dont find it in 1st zip , then browse to another 2nd zip file folder and check the second update.app

Eventually you will find all these 3 files. Keep them safe.

Copy them to SRK tools folder.

Now please do the following steps.

Switch off the phone

Put the phone in fastboot mode. (or bootloader mode both are same) ( how to enter into fastboot mode ? - check the steps above)

Connect it to laptop

Open SRK tools

Type 000

you will enter command prompt

Your phone should be recognized automatically if you are using windows 10. ( you need to install adb driver -> UniversalAdbDriverSetup6)

Then type the following commands

fastboot flash recovery recovery.img

fastboot flash boot boot.img

fastboot flash system system.img

once you finish the above 3 steps , type

fastboot reboot

Your phone will reboot but you might have blank screen & it might look as if nothing worked. But dont panic.

Just switch off your phone

Go to Recovery mode (not erecovery) - it will be stock recovery

And do factory reset.

Wait for a while.

After some time you will get that setup starting with language followed by other steps.

But remember we did this only to get your phone working properly. It is not complete ROM yet. Here you have a choice. you can either skip downgrade to marshmallow steps & go directly to bootloader unlock steps or go through the downgrade to marshmallow steps if you want to do it properly & then do a system update to L29C636B585. I would advise you not to skip the downgrade process because, at this point in the process, you still don't have complete ROM

How to go back to marshmallow?

First, you need rollback package for L29C636BXX

put the update.app in folder called dload in your SD card

This file should be around 90 mb or so .

After it finishes the dload process, the build number will be C900BXX

That means it is ready to downgrade to marshmallow

Get a stock ROM NXT-L29C636B191

This file seems to be hard to get, try to search in google and find this file.

Once you do, extract the zip file and put the update.app in dload folder in SD card and do the dload process again.

After the dload process is finished, you will now be in L29C636B191. Now just connect to your WIFI & you should see system update notification to update to L29C636585. In another half an hour or so you will be in L29C636B585. You have to be patient. and wait for the process to complete.

then your phone will be Stock ROM & stock recovery with bootloader locked properly. Now you can proceed to unlock your bootloader.

Go to settings - > about phone -> tap 7 times on build number - > Developer options will now be enabled in your settings.

Go to the developer options

Enable - OEM unlocking

USB debugging - ON

Switch off the phone

Put the phone in fastboot mode ( see above for steps )

connect it to laptop

Open SRK tools

type 000

In the command prompt

type

fastboot oem unlock xxxxxxxxxxxxx

that xxxxxxxxxx is your bootloader unlock code that you can get it for free from Huawei website.

This is how you can properly unlock bootloader on your phone.

I understand completely that this is a lot of steps but you mentioned the status of your phone. So to do it properly without any errors this is how you can do. If your phone was booting normally and you are able to go inside the OS then you just have to use rollback package (dload) & then dload to marshmallow followed by system update to L29C636B585. When your phone has problems only rollback package will succeed in dload method. No other file will.

Do these steps very carefully, slowly and be patient. Order of the steps is very important so please remember that too.

When you reply, dont quote this post entirely, just quote one sentence. And do let me know your progress. Please mention clearly about what you did & how you did, files used etc in detail to help you quickly & properly. Try to get the files I have mentioned above. They are very important.

If you do these steps you should be able to revive your phone to normal state & unlock bootloader properly. So good luck. Hope you succeed.

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