You have the Chinese hardware/software version of M3. It's different to the international version. The Chinese version is focussed on Chinese streaming services whereas the international version has these removed and is mainly a media player.
With Q5/Q10 4K3D the two hardware versions are incompatible for firmware. I'm not 100% sure if it's the same for M3, but I suspect it will be.
So if you flash the international firmware on a Chinese M3 there is a high probability you'll permanently brick it.
It is impossible to back up the firmware. The international firmware, if it did install which I suspect it won't, will not give you access to the Chinese streaming services you want.