Hi hasnaadams7 Thank you for your asking. For ZC551KL, there will no longer have any maintenance. Sorry for any inconvenience it may cause. Thank you for your understanding and support. Besides, 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. If you still want to unlock the device, you may check for other forums created by power users.