MDREFR_K1DB2
#define MDREFR_DB2_MASK (MDREFR_K2DB2 | MDREFR_K1DB2)
sd->mdrefr |= MDREFR_K1DB2;
sd.mdrefr |= MDREFR_K1DB2;
sd.mdrefr &= ~MDREFR_K1DB2;