Edited by ArasBekar at 2018-01-11 19:51
Well, 5.3.7.0.G is not real International firmware. It is dump from G that was laied on A firmware. You should download A version (i will give you a ling to Yandex disc with the latest 6.2.5.1A) and after that you should try to set your G as you have done it before. Every time(!!!) you must check "Clear Data"
1.  https://yadi.sk/d/wqQYq8dH3RHZuF    download update.zip  (this is A latest firmware. download should be faster then from Ch Flyme site)
2.  https://yadi.sk/d/ZQgf5Eq93RMqi3      this is 5.2.7.0 G for more faster download

Thank You so much!
So, I'm not mistaken, first go to A, and then I can flash the G (Global) version? And then it will refresh to Flyme 6.x.x.xG?
Tomorrow I'll try it!
Thanks again!
J

Yeah, you are not mistaken. Waiting your results

So, I'm back again!
I've tried to flash normally the "G" version, after downloading from official website, but there was a problem again. 'Cause I had 5.3.x.x.G, which was a chinese version, as You mentioned before, it gave a "firmware corrupt" issue again. But no problem, I've tried to upgrade to 6.x.x.x.A (chinese version, Flyme 6), and voila', everything worked properly!! I'had a chinese version, with the latest, but not a problem, it contained english language. Battery time become awesome, much better then Flyme 5. There were some chinese applications, but who cares. Everything works properly.

Meantime I've read about this story, and found something interesting:
https://forum.xda-developers.com/pro-6-plus/how-to/how-to-install-flyme-os-6-7-4-11-global-t3595361

Check this! If You have a chinese device, it's the solution. A step-by-step procedure, how to flash the latest Flyme 6 Global.
Just simply download the Flyme 6 version, You can find on the page, download and install SuperSu, and FlashFire on your device, and check the detailed step-by-step procedure.
In my case, it worked properly. Now I've a Global one, with the latest Flyme 6, I hope so... :-)
Just check the GMS (Google Mobile Services) in the Application Store, and then You have Google applications and play store.

So I'd like to say a great thank You for Your advices! It started me on the correct way to solve my problems!

J

You are welcome! Glad that i was able to help!