Is your bootloader unlocked? If not you cant. If yes, then you may search for global rom on firmware finder app. It should be C900 rom
The phone was SU preloaded, i think the bootloader should already unlocked, i have the "Firmware finder Huawei App" installed on the my phone, but i couldn't sure the rom to download, based on the current build number BND-AL00C00B201, there are two OTA availlable, but is it still the same chinese rom?
I have similar problem but I already flashed custom how to tell??
https://xdaforums.com/honor-7x/help/7x-pie-bnd-al10-t3922633