LCD_2004_VB not reading SD card

[mianwo]

I don't know if I'm just bad luck, but here's my problem:

The LCD unit comes with the kit (G2S pro) doesn't read SD card.
I have another working 3d printer, a prusa i3, when I plug the LCD unit from that printer to G2S, everything works fine. And when I plug the LCD from G2S to the i3, same problem, not reading SD card at all. So I concluded that the G2S LCD unit is faulty and asked customer service for a replacement unit.

The replacement came, but to my surprise, it has the same problem!
Now I have no clue, if the LCD unit is suppose to work, what are the chances of both units having exactly the same issue?

What I know for sure is that the 2 units comes from Geeetech don't work on both G2S and my old i3, and the unit on the i3 works on both printers.

[William]

As to the SD card issue,here are some tips for you:
1、Use Repetier Host to put files on SD-card and the G-codes have been also in root directory of SD-card.
2、Check the connection between the SD card and the main board and check if the welding condition of the SD card slot and LCD panel is defective.You can post some pictures about it.
3、Choose some new SD Cards which are in better quality, and try different sizes or formats ;
The USH-1 and Class10 SD Cards are not supported by Printer.
4、Reinstall the FTDI drivers.
Please feel freely to let me know your lastest situation.