LEMTU
if (len < LEMINSIZE + 4 || len > LEMTU) {
rmd->rmd2 = -LEMTU;
lemem->lem_rmd[i].rmd2 = LE_XMD2_ONES | -LEMTU;
volatile uint8_t lem_rbuf[LERBUF][LEMTU];
volatile uint8_t lem_tbuf[LETBUF][LEMTU];