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How To Guide WARNING: Read BEFORE Locking Bootloader

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DO NOT LOCK THE BOOTLOADER WHILE ROOTED!

When locking the bootloader while rooted, the boot image will fail verification and the system will fail to boot. You cannot flash a stock boot image with a locked bootloader.

Locking the bootloader will not fix most issues. It will allow you to use apps that check for an unlocked bootloader without the need for any additional modification. That is the ONLY benefit.

If you still want to lock your bootloader, make sure you can say yes to each of the following:

1. Have you restored the stock boot.img / vendor_boot.img and the phone functions normally?
Follow the instructions in the thread above.
Use only the boot and vendor_boot images.
Do NOT flash any images that end with "-magisk.img"
2. Have you made a backup of everything you do not want to lose when wiping the phone?
The sdcard is part of the internal storage and is cleared by a factory reset
Copy everything you want to keep to a computer or USB-C storage device
Apps and settings can be backed up by enabling the Google Backup option
  • Open Settings
  • Select Google
  • Select Backup
  • Select Back up now
  • Wait for the backup to complete
3. Have you flashed raw firmware and made sure the phone and updates function normally?
Follow the instructions in the thread above.
If you perform a wipe, you may skip step 4.
4. Have you performed a factory reset and made sure the phone functions normally?
  • Open Settings
  • Select System
  • Select Reset options
  • Select Erase all data (factory reset)
  • Follow the instructions

Once you have verified all of the above requirements, you are now ready to lock the bootloader.
From the bootloader (volume up + power):
Code:
fastboot oem asus-csc_lk
 
Last edited:

falhumai96

Member
Jun 26, 2017
26
6
I don't want to spread false information here, but here is a question post I created recently with two replies showing me contacting the help center (two different agents) confirming that I can use the app more than once to unlock the device's bootloader: https://forum.xda-developers.com/t/...nlock-relock-for-asus-rog-phone-5-5s.4367047/ . @Andrologic also confirms the case there for global (EU) version. I have a feeling that for the Tencent version it is because the sellers lock it on a wrong official ROM, or wrong ROM in general, e.g. global ROM, and therefore it confuses the unlock app. I am surprised the device did not even get hard bricked from locking on not the original ROM. By the way, I have contacted the help center of the US store, but I have a feeling it should work on the global (EU) version as well.
 
I don't want to spread false information here, but here is a question post I created recently with two replies showing me contacting the help center (two different agents) confirming that I can use the app more than once to unlock the device's bootloader: https://forum.xda-developers.com/t/...nlock-relock-for-asus-rog-phone-5-5s.4367047/ . @Andrologic also confirms the case there for global (EU) version. I have a feeling that for the Tencent version it is because the sellers lock it on a wrong official ROM, or wrong ROM in general, e.g. global ROM, and therefore it confuses the unlock app. I am surprised the device did not even get hard bricked from locking on not the original ROM. By the way, I have contacted the help center of the US store, but I have a feeling it should work on the global (EU) version as well.

Based on new information, it does seem possible to repair the issues caused by converting.

That said, this guide is still quite relevant. After all, most of the issues people were having were caused by unlocking the bootloader, converting, rooting, and locking the bootloader. The warning for possibility of not being able to unlock have been removed, but the info about restoring to stock before locking has been left.
 
Last edited:
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chairman011

Senior Member
Nov 11, 2012
187
56
houston
I send mine in for a motherboard repair I was rooted and everything I unrooted installed stock firmware and locked the bootloader again once I got the phone back I unlocked the bootloader once again and I am rooted again
 
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Reactions: falhumai96

falhumai96

Member
Jun 26, 2017
26
6
I send mine in for a motherboard repair I was rooted and everything I unrooted installed stock firmware and locked the bootloader again once I got the phone back I unlocked the bootloader once again and I am rooted again
@chairman011 what variant of the phone it is (e.g. CN or WW or US, ...etc.)? Also, when they returned it to you and you were able to unlock it again, was it on the original firmware (or any version in its lineage (i.e. not a ROM that's not original))?
 

falhumai96

Member
Jun 26, 2017
26
6
If by using ASUS unlock utility one was able to oneself unlock the boot-loader once, then is it safe to say that (after relocking it) it'd be possible to unlock it again?
Some people have reported that you can't unlock the bootloader again after relocking, using the official "Unlock Device App", but I suspect it is an OS mismatch. This issue has only been observed on Tencent (CN) version with global ROM. Have anyone been able to unlock->relock->unlock on the same version of the phone, but not relocking while on the global ROM (i.e. relocking while on stock CN ROM)?

I am surprised the phone did not hard brick. Usually, and this is a general case in almost all Android phones with bootloader unlock capability, when you relock on a different ROM your phone hard bricks. Always restore to original ROM before relocking. Can people with Tencent (CN) phones with global ROM and locked bootloader flash the original CN ROM without unlocking the bootloader? If so, can you test the "Unlock Device App" to see if it works while on the CN (official) ROM? I gotta a feeling it might work in that situation.
 
Some people have reported that you can't unlock the bootloader again after relocking, using the official "Unlock Device App", but I suspect it is an OS mismatch. This issue has only been observed on Tencent (CN) version with global ROM. Have anyone been able to unlock->relock->unlock on the same version of the phone, but not relocking while on the global ROM (i.e. relocking while on stock CN ROM)?

I am surprised the phone did not hard brick. Usually, and this is a general case in almost all Android phones with bootloader unlock capability, when you relock on a different ROM your phone hard bricks. Always restore to original ROM before relocking. Can people with Tencent (CN) phones with global ROM and locked bootloader flash the original CN ROM without unlocking the bootloader? If so, can you test the "Unlock Device App" to see if it works while on the CN (official) ROM? I gotta a feeling it might work in that situation.

It's an identification mismatch. It's similar to when you throw your SIM card in a different phone and your carrier lists you as having a different phone. Based on the information that has been discovered, it would appear that CN to WW conversions were wiping out the stuff that makes your device your device.
 

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  • 2
    If by using ASUS unlock utility one was able to oneself unlock the boot-loader once, then is it safe to say that (after relocking it) it'd be possible to unlock it again?
    Some people have reported that you can't unlock the bootloader again after relocking, using the official "Unlock Device App", but I suspect it is an OS mismatch. This issue has only been observed on Tencent (CN) version with global ROM. Have anyone been able to unlock->relock->unlock on the same version of the phone, but not relocking while on the global ROM (i.e. relocking while on stock CN ROM)?

    I am surprised the phone did not hard brick. Usually, and this is a general case in almost all Android phones with bootloader unlock capability, when you relock on a different ROM your phone hard bricks. Always restore to original ROM before relocking. Can people with Tencent (CN) phones with global ROM and locked bootloader flash the original CN ROM without unlocking the bootloader? If so, can you test the "Unlock Device App" to see if it works while on the CN (official) ROM? I gotta a feeling it might work in that situation.
    1
    I don't want to spread false information here, but here is a question post I created recently with two replies showing me contacting the help center (two different agents) confirming that I can use the app more than once to unlock the device's bootloader: https://forum.xda-developers.com/t/...nlock-relock-for-asus-rog-phone-5-5s.4367047/ . @Andrologic also confirms the case there for global (EU) version. I have a feeling that for the Tencent version it is because the sellers lock it on a wrong official ROM, or wrong ROM in general, e.g. global ROM, and therefore it confuses the unlock app. I am surprised the device did not even get hard bricked from locking on not the original ROM. By the way, I have contacted the help center of the US store, but I have a feeling it should work on the global (EU) version as well.

    Based on new information, it does seem possible to repair the issues caused by converting.

    That said, this guide is still quite relevant. After all, most of the issues people were having were caused by unlocking the bootloader, converting, rooting, and locking the bootloader. The warning for possibility of not being able to unlock have been removed, but the info about restoring to stock before locking has been left.
    1
    I send mine in for a motherboard repair I was rooted and everything I unrooted installed stock firmware and locked the bootloader again once I got the phone back I unlocked the bootloader once again and I am rooted again
  • 3
    DO NOT LOCK THE BOOTLOADER WHILE ROOTED!

    When locking the bootloader while rooted, the boot image will fail verification and the system will fail to boot. You cannot flash a stock boot image with a locked bootloader.

    Locking the bootloader will not fix most issues. It will allow you to use apps that check for an unlocked bootloader without the need for any additional modification. That is the ONLY benefit.

    If you still want to lock your bootloader, make sure you can say yes to each of the following:

    1. Have you restored the stock boot.img / vendor_boot.img and the phone functions normally?
    Follow the instructions in the thread above.
    Use only the boot and vendor_boot images.
    Do NOT flash any images that end with "-magisk.img"
    2. Have you made a backup of everything you do not want to lose when wiping the phone?
    The sdcard is part of the internal storage and is cleared by a factory reset
    Copy everything you want to keep to a computer or USB-C storage device
    Apps and settings can be backed up by enabling the Google Backup option
    • Open Settings
    • Select Google
    • Select Backup
    • Select Back up now
    • Wait for the backup to complete
    3. Have you flashed raw firmware and made sure the phone and updates function normally?
    Follow the instructions in the thread above.
    If you perform a wipe, you may skip step 4.
    4. Have you performed a factory reset and made sure the phone functions normally?
    • Open Settings
    • Select System
    • Select Reset options
    • Select Erase all data (factory reset)
    • Follow the instructions

    Once you have verified all of the above requirements, you are now ready to lock the bootloader.
    From the bootloader (volume up + power):
    Code:
    fastboot oem asus-csc_lk
    2
    If by using ASUS unlock utility one was able to oneself unlock the boot-loader once, then is it safe to say that (after relocking it) it'd be possible to unlock it again?
    Some people have reported that you can't unlock the bootloader again after relocking, using the official "Unlock Device App", but I suspect it is an OS mismatch. This issue has only been observed on Tencent (CN) version with global ROM. Have anyone been able to unlock->relock->unlock on the same version of the phone, but not relocking while on the global ROM (i.e. relocking while on stock CN ROM)?

    I am surprised the phone did not hard brick. Usually, and this is a general case in almost all Android phones with bootloader unlock capability, when you relock on a different ROM your phone hard bricks. Always restore to original ROM before relocking. Can people with Tencent (CN) phones with global ROM and locked bootloader flash the original CN ROM without unlocking the bootloader? If so, can you test the "Unlock Device App" to see if it works while on the CN (official) ROM? I gotta a feeling it might work in that situation.
    1
    I don't want to spread false information here, but here is a question post I created recently with two replies showing me contacting the help center (two different agents) confirming that I can use the app more than once to unlock the device's bootloader: https://forum.xda-developers.com/t/...nlock-relock-for-asus-rog-phone-5-5s.4367047/ . @Andrologic also confirms the case there for global (EU) version. I have a feeling that for the Tencent version it is because the sellers lock it on a wrong official ROM, or wrong ROM in general, e.g. global ROM, and therefore it confuses the unlock app. I am surprised the device did not even get hard bricked from locking on not the original ROM. By the way, I have contacted the help center of the US store, but I have a feeling it should work on the global (EU) version as well.

    Based on new information, it does seem possible to repair the issues caused by converting.

    That said, this guide is still quite relevant. After all, most of the issues people were having were caused by unlocking the bootloader, converting, rooting, and locking the bootloader. The warning for possibility of not being able to unlock have been removed, but the info about restoring to stock before locking has been left.
    1
    I send mine in for a motherboard repair I was rooted and everything I unrooted installed stock firmware and locked the bootloader again once I got the phone back I unlocked the bootloader once again and I am rooted again