Cheats for Dreamcast System (DC)

Controller reset
Hold A + B + X + Y and press Start in most games to do a soft reset.

Delete internal memory settings
Hold A + B + X + Y and turn on the Dreamcast. Then, release the buttons after the date/time prompt appears. Note: This will not affect your VMU memory and will only reset internal information, such as date, time, and Dreamcast Network settings.