How to Flash or Install Firmware (ROM) Download and extract the Asus Zenfone Max Pro M2 ZB630KL stock firmware package on the computer. After extracting the package, you will be able to get the Firmware File, Flash Tool, Driver, and How-to Flash Guide. Install the provided USB Driver on the computer The Flash file lets you upgrade and downgrade the stock firmware to your Asus ZenFone Max Pro M2 Android smartphone devices. Flash files can also help you to fix software problems, booting process, IMEI problems, and Android smartphone problems. X0z2.