i’ve the same problem. My M3 Max has an “A” (chinese) firmware and i want to change to “G” (international/global) Firmware. You can download the official global firmware here. But: when you try to install the global firmware, it always says “firmware corrupted”. Thats because the Device ID says its a china phone, you have to change it to international.
At the M2 Note and M3 Note you can root your phone using the flyme account and use a script (for example it’s named “chid.sh”) in a terminal emulator app to change the device ID, so that the phone ID changes to the international version, than you can install the global rom the normal way.
A user at 4pda.ru has already made this script, but i can’t download it! (Page 2, post 39 - Filename: “max-m3 chid.7z”). Here are the links: Russian, English translated
the problem is, when you try to download the file, website gives a 404-error
With this file we all can change to global.
Can someone with a 4pda Account check this and download the file?