How To Relock Bootloader of Zenfone Max (M1) ZB555KL

[Robertzon]

Please tell us some basic information before asking for help:
Model Name:
Firmware Version:
Rooted or not:
Frequency of Occurrence:
APP Name & APP Version (If your issue relates to the app):
In addition to information above, please also provide as much details as you can, e.g., using scenario, what troubleshooting you've already done, screenshot, etc.
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[Christine_ASUS]

Hi Robertzon
Thank you for your asking.
First, please note that unlocking the device or flashing the custom ROM are quite risky, may causing security issues like Widevine Issue, banking app usage issue, or unexpected software issues. Second, any unlocked/rooted/custom rom device will be regarded as out of warranty device, revised device. Last, officially, we do not provide lock back service/tools. Once the device is unlocked, the server will have related record and it can never be revised even if you lock the device back by yourself.
If you want to lock back your device unofficially, please check some power users' forums for more information.