TXP_H2A_1
WRITE_REG(sc, TXP_H2A_1, fileheader->addr);
WRITE_REG(sc, TXP_H2A_1, sect->nbytes);
sc->sc_txhir.r_reg = TXP_H2A_1;
WRITE_REG(sc, TXP_H2A_1, vtophys(sc->sc_boot));
WRITE_REG(sc, TXP_H2A_1, TXP_BOOTCMD_NULL);