Ok... Lets go! Download this fastboot rom file (its the global stable) http://update.miui.com/updates/v1/fullromdownload.php?d=davinci_global&b=F&r=global&n=
You can download it from here too, but remeber! YOU NEED FASTBOOT VERSION!
You will notice that is mucth bigger and after unpacking it (pehaps, you will need do decompress it twice) it will double the size (6,5 gb). You need .tgz file. If the ROM file suffix is '.gz', just rename it to '.tgz')
Now, download this 2017 mi flash toll http://api.en.miui.com/url/MiFlashTool. You can try the newest version, but I suggest that one. Install it.
Turn off the device. Press the Volume– key and the Power button at the same time to enter Fastboot mode. Then connect the device to the Windows PC/laptop via a micro USB cable.
Open mi flash toll, search for the rom, click refresh and do it!
This should no take long! It may look that is stuck on 99%, but if the phone reboots, you can disconnect the cable! If did not work, try EEA Stable ROM, also found here https://mirom.ezbox.idv.tw/en/phone/davinci/
We already tried this exactly like that.
Does not work.
Although I only decompressed it once. Idk how u supposed to do it twice. If u unzip once it's already unzipped. Like u can't unzip a normal folder.