Just bought myself a Kompatibel RepRap RAMPS LCD 12864 Controller with LED Turn On Control for 3D Printer
I'm using RAMPS 1.4, marlin and have uncommented #define REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER
This seems to work for everything, until I insert an SD card which causes all control to freeze, only the removal of the card and a restart gets things going again.
I have also tried to no avail:
//#define SDSUPPORT // Enable SD Card Support in Hardware Console
//#define SDSLOW // Use slower SD transfer mode (not normally needed - uncomment if you're getting volume init error)
//#define SD_CHECK_AND_RETRY // Use CRC checks and retries on the SD communication
What Format are you using for the SD card ?, Maybe that is the problem :-/