FINALLY I've found a method!!! It works for 7 Pro H. (Chinese version on a Helio X30, 128 GB)
1. Go to needrom.com/download/meizu-pro-7-h-no-pro-4gb-128gb-helio-x30-custom-international-firmware/
Register, and download .zip file from above
2. Unpack on a desktop
3. Connect your 7Pro H as a CD-rom, - adb drivers should be installed automatically.
4. Run adb.exe, restart a computer
5. Create a txt file (right mouse click) with only a line - 0x2a45. Save as adb_usb.ini Copy this file to C:\Users\USER NAME\.android
6. Activate a Developer mode on your phone by tapping several times on a “Firmware version” in “About a phone” menu.
7. In a “Dev. Mode” turn on “USB debugging”
8. Connect a phone as a MTP
9. Run “Start.cmd” from a folder on a destop (step 2)
10. When appears “Connect via ADB, please arouse your phone and allow the connection in the popup window…” - confirm an access on a phone screen
11. In a window of Start.cmd
a. Press 1 to perform a full backup
or
b. Press 2 to flash
12. There is no progress bar, so just be patient.
13. It takes about 10-12min.
14. After you receiving 2 messages about flashing 2 files (of 500 and 2500 MB) press any key.
Phone will boot into recovery, press CANCEL
Wipe or not data – it’s up to you. I’ve flashed over Chinese beta 6.7.12.12 with no wipes – everything (apps) works fine.
ROOT access is also remains from a previous fw.
Done. Enjoy!
NB. There is no Flyme account and no OTA as well. If you need root - root your current fw, then flash as above with no wipes.
Firmware works perfect!