[General Topics] izyer:
(some infos are from 4pda - translated with google)

The bootloader must be unlocked (three small lines "Orange state ..." are visible on the DuoQin boot screen).

You can take 1.0.7 ROM and unlock it Fastboot flashing unlock .

Save dump for recovery in case of something goes wrong.

INSTRUCTIONS for flashing the multilingual version of NVT (similar to 1.9.8) with Google Play without Chinese applications. (with and without ROOT)

All you need is FlashTool and drivers for it .

1) Turn off the phone with an unlocked bootloader.

2) In FlashTool, select the Qin F22 Pro Root.txt file in the scatter field .

3) In rows with sections, all checkboxes are enabled.

4) Click Download, then connect the phone to USB.

5) Upon completion, disconnect the phone from the cable, turn it on, get into Recovery . Choose Wipe All and Reset . We are overloading.

6) Turn on the phone, connect to the network. Magisk will ask you to update.

7) After the reboot, install the keyboard (for example, Yandex).

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Root can be deleted at any time (in Magisk, the "Delete Magisk" button).

Root can be installed at any time "on top" of the working system: 1) Run SP FT, select Qin F22 Pro Root.txt

as a scatterer . 2) Set the checkbox only on the boot_a partition (ThanR.img file). 3) Click Download, then connect the phone to USB.

4) After turning on, install Magisk, let it update.

Links:

1) Some backup i took with MTKCLIENT from my phone before flashing (unlocked, i had this ROM on my phone before Flashing the NVT version): https://files.fm/u/cvxzz2gaq

2) ROM V1.1.0 MTKCLIENT backup / CH original version , no google play (locked) https://dox.abv.bg/download?id=27ac8ae238#

3) ROM V1.0.7 without google play but unlocked: {Mod edit: Link to paid services website removed. Oswald Boelcke, Senior Moderator} (you may need to flash this first with Fastboot flashing before flashing NVT ROM version so you can have an unlocked phone requierd to flash NVT ROM or you can flash my backup from link 1 with MTKclient)

4) The ROM you want , multilingual version of NVT (similar to 1.9.8) with Google Play : https://drive.google.com/file/d/1gQE6MboV2jjI822cI2xdhlkxF-IvZawg/view

The password is "than"

What ive noticed , VoWifi option doesnt work from the settings menu (crashes if you try to enable it) , you need some 3rd app to enable the switch (then it works) , Call Log (phone app, and few others) are not fully translated (like 90% translated , but its OK) and the main launcher is still limited , you cant change any settings (for home screens etc.. but you can install some other launcher from Google Play) , everything else seems to work.

With my last ROMs (EN /CH version with Google Play and ROM V1.0.7) i had some microphone troubles and people on the other end of the call were hearing me in a very poor quality (and echo) some work around was to install the Google Phone App and in the settings i could find an option called Noise Suppression and i have to disable it (then i could remove the app), the sound was still bad and sometimes echo-ing but it was better than before. (VoLTE and VoWIFI were not working at all on this ROMs)

I didnt test the quality with the NVT ROM yet (but VoLTE and HD Call seems to work, hopping they fixed the codecs or what was wrong in the other ROMs) but if anyone has this kinda problems they can do what ive explained , install Google Phone app and disable Noise Suppression, i cant find this option without installing that.

With the original ROM that this phone came with , it had a PURE GOOGLE VERSION with Google Play (not a factory ROM), everything was working fine (including the Call Quality) but the KEYPAD was NOT mapped and you couldnt use it to do many functions as it was intended (you couldnt End Call, pressing cancel button was shutting down the screen instead of canceling , you couldnt navigate ok using they keypad etc.. , )

{Mod edit: Hyperlinks to 4pda removed! Oswald Boelcke, Senior Moderator}