You need to install USB Driver, so your PC recognize the tablet
1. Extract the SystemUSB.zip
2. Turn off the tablet.
3. Connect the PC and the tablet using USB cable.
4. Connect the tablet to its charger.
5. Put the tablet into nvflash mode.
6. If successful, you’ll hear a notification sound from your PC.
7. Your PC will ask you to install a driver for the new APX device connected.
8. Choose to install the driver from specific location.
9. Locate the driver in the folder where you extract SystemUSB.zip
Now you can proceed to any flashing procedure using nvflash program.
To put the tablet into nvflash mode:
You need to connect the tablet to its charger, and press a certain button combo.
A lot of tutorial said press and hold 2 second etc, in my experience, it is not necessary.
The important thing is the right sequence.
1. Back Button, press and hold,
2. Power Button, press and,
3. Release both when you hear notification sound from your PC