ASUS does not provide an official tool to relock the bootloader. Attempting to lock it manually via fastboot oem lock will likely corrupt your device signature, resulting in a hard brick. If you need to return to factory state, you must flash the full stock raw firmware using ASUS’s Flash Tool, but the bootloader status may remain "unlocked."
Q: Will unlocking the bootloader improve battery life on my Zenfone 9? A: Not directly. However, after rooting, you can install kernel managers (like Franco Kernel Manager) or apps like Naptime to aggressively optimize doze mode, potentially improving screen-off battery life. zenfone 9 unlock bootloader
Q: Can I receive official ASUS OTA updates after unlocking? A: Yes, but you must have a stock, unmodified system partition. If you have root or a custom kernel, the OTA will fail. You will need to flash the stock boot image first, update, then re-root. ASUS does not provide an official tool to
Q: Does the Zenfone 9 have a "real" fastboot mode? A: Yes. To enter: Power off, then hold Volume Up + Power. Use volume keys to navigate to "Fastboot" and press power to select. Q: Will unlocking the bootloader improve battery life
Q: My banking app says "Device is rooted" even though I only unlocked the bootloader.
A: Unlocking the bootloader alone trips Google’s verifiedboot flag. You need to install Magisk and use Zygisk + Shamiko module to hide the bootloader status from banking apps.
fastboot flash boot magisk_patched.img