@tonemaewbin
We would like to inform you that we no longer provide previous firmware versions or downgraded software packages on ASUS official website. This is to ensure that the security updates on your phone remain up-to-date with the latest firmware versions. We appreciate your understanding and patience. If you have any question or need assistance, please feel free to visit our service center or call the service hot line, we will do our best to provide help for your questions.
The following is the contact information:
https://www.asus.com/support/service-center-location
Also you can contact the local service center for help.
The following is the contact information:
https://www.asus.com/support/CallUs#
Sorry for any inconvenience it may be caused.
