ardupilot/libraries/AP_AIS/AP_AIS_config.h

#pragma once

#include <AP_HAL/AP_HAL_Boards.h>

#ifndef AP_AIS_ENABLED
#if BOARD_FLASH_SIZE <= 1024
    #define AP_AIS_ENABLED 0
#else
    #define AP_AIS_ENABLED 2
#endif
#endif