>>/990864/
Just did my Mudman G-9000MS-1 (3031 module) and had to:
Hold the Adjust (top-left) button in timekeeping mode until it beeps/flashes,
Press Mode (bottom-left) to find the "DST" setting, then use the Stop/Start button (bottom-right) to select "OFF",
Press Adjust (top-left) to save.
Regret getting the light-on-dark tacticool operator LCD, it's a pain in the cunt to read in daylight.