1.New SD card must to be format to the one that can be recognized by the screen.
Start=>> running=>> Input command to enter DOS system(win7 system, please input cmd), input format/q g:/fs:fat32/a:4096.
G is the disk number of your SD card. Please noted that right click to format is invalid; SD card capacity must within 2-16G.
2.Then Put the File I send into the SD card, plug the SD card into the touch screen.
3.Turn on the printer, and it will flash by itself.
4.Power off , remove the SD card and restart.
Then please flash the firmware for the mainboard, connect the printer and computer with usb cable, find out "Update firmware" in Cura software,
Firmware download: https://sovol3d.com/pages/download