There are multiple versions of Dragon Mint T1 that vary in control board type and revision.

Control board

The notes here are relevant for Xilinx based control board are marked G9 and G19 and G29. Unfortunately, the G29 doesn’t have an SD card slot populated.

Boot Modes

The table below shows J1-J4 settings for selecting the boot mode.

Boot Mode J1 J2
NAND 0 0
SD Card 0 1