this header is from the bad mario kart rom on the net (didn't have the right one around), but it works anyways (as in, the graphics are working).
08C2388B4BAB48DA5AAD1042E6342081B1AF360000AAFCBF817AFA68AB286B08C2388B4BAB48DA5AE230A6D0AD1142FC128BC2307AFA68AB286B4BAB9C00429C
I used 'ucon f mkart.smc' to convert it, which creates two 256 kb files.. it will not work otherwise.