Power on and connect your Minix Mini to your PC using the supplied Male-Male USB cable.
If the device won’t be detected by the PC then enable the Enable “Connect to PC” on Android Settings -> USB.
Now your PC will detect the device as external storage.
Now, unplug the power and usb cable from X7mini. Connect the usb cable first. While keeping the reset button pressed (at the bottom of the x7mini; use a pin) , plug in the power. Keep the reset button pressed for another 4-6 seconds and release. At this point, the Windows PC should be connected to the X7mini and the PC goes into a looking-for-driver search mode. When prompted (after exhausting the auto search), point the PC to the driver folder location above. Remember to use the correct location relevant to your PC config (e.g. x7mini\NEO_USBdriverV3.5\Win32bit\win7).If it does not prompt, go to device manager on the windows and configure the driver manually.
Once this is successfully completed, run RKbatchtool.exe. It should show a “connected devices” square icon in GREEN. Choose RESTORE (Important: do NOT use Upgrade) button and point to the firmware file in the folder created in Step 1. The firmware upgrade will begin and do not press any buttons or unplug anything until the process is fully finished.
The X7mini will reboot itself with the newly updated firmware, the whole process may take upto 10 mins.
Thanks to Niruban from minix forums.all credit to him!