This is an adapter that allows you to use various USB controllers on the Dreamcast console. It is a handmade product. For more details, search for "Dreamcast USB4MAPLE". As shown in the image, connecting an SD card via a USB hub allows you to use the SD card as a memory card. I have tested it with the 8bitdo M30 2.4g and confirmed that it works. I have also confirmed that saving works without any problems. I have multiple units in stock, so please let me know if you are interested. The price on this page is for one unit. One unit costs 1500 yen. Thank you for looking.