1.U can unzip recovery from official ROM file that file’s name is end with “.zip” . I’d tried to find recovery in Chinese edition and it was named to “recovery.img” in the root folder of ROM file.
2.After U got the recovery image, u need to flash it to your phone in bootloader or just boot it with command “fastboot boot xxx.img”. ***.img is the name of your recovery file.
3.Choose the language which U can understood , Clear user data(This option maybe clear EVERYTHING on UR phone!!! However my phone is.) - Clear Cache - Reboot to Official recovery and clear data and cache again.
4.Then, choose the ROM file and wait for it finish.
NOTICE: My device is NX549J. When I tried back to official ROM I will need for an SD card to store official ROM on it for the Third-part ROM won’t support OTG on official recovery.