diff --git a/sys/dev/ahci/ahci.c b/sys/dev/ahci/ahci.c
index 062abc0b8c0d..91c28b46f286 100644
--- a/sys/dev/ahci/ahci.c
+++ b/sys/dev/ahci/ahci.c
@@ -2578,10 +2578,10 @@ ahci_setup_fis(struct ahci_channel *ch, struct ahci_cmd_tab *ctp, union ccb *ccb
 		fis[9] = ccb->ataio.cmd.lba_mid_exp;
 		fis[10] = ccb->ataio.cmd.lba_high_exp;
 		fis[11] = ccb->ataio.cmd.features_exp;
+		fis[12] = ccb->ataio.cmd.sector_count;
 		if (ccb->ataio.cmd.flags & CAM_ATAIO_FPDMA) {
-			fis[12] = tag << 3;
-		} else {
-			fis[12] = ccb->ataio.cmd.sector_count;
+			fis[12] &= 0xf8;
+			fis[12] |= tag << 3;
 		}
 		fis[13] = ccb->ataio.cmd.sector_count_exp;
 		fis[15] = ATA_A_4BIT;
diff --git a/sys/dev/mvs/mvs.c b/sys/dev/mvs/mvs.c
index f6d2ef240c2b..e018aba5bdea 100644
--- a/sys/dev/mvs/mvs.c
+++ b/sys/dev/mvs/mvs.c
@@ -1493,7 +1493,8 @@ mvs_execute_transaction(struct mvs_slot *slot)
 		crqb->cmd[i++] = ccb->ataio.cmd.features;
 		crqb->cmd[i++] = 0x11;
 		if (ccb->ataio.cmd.flags & CAM_ATAIO_FPDMA) {
-			crqb->cmd[i++] = slot->tag << 3;
+			crqb->cmd[i++] = (slot->tag << 3) |
+			    (ccb->ataio.cmd.sector_count & 0x07);
 			crqb->cmd[i++] = 0x12;
 		} else {
 			crqb->cmd[i++] = ccb->ataio.cmd.sector_count_exp;
diff --git a/sys/dev/siis/siis.c b/sys/dev/siis/siis.c
index bf3448068731..f853412b5b24 100644
--- a/sys/dev/siis/siis.c
+++ b/sys/dev/siis/siis.c
@@ -1723,13 +1723,12 @@ siis_setup_fis(device_t dev, struct siis_cmd *ctp, union ccb *ccb, int tag)
 		fis[9] = ccb->ataio.cmd.lba_mid_exp;
 		fis[10] = ccb->ataio.cmd.lba_high_exp;
 		fis[11] = ccb->ataio.cmd.features_exp;
+		fis[12] = ccb->ataio.cmd.sector_count;
 		if (ccb->ataio.cmd.flags & CAM_ATAIO_FPDMA) {
-			fis[12] = tag << 3;
-			fis[13] = 0;
-		} else {
-			fis[12] = ccb->ataio.cmd.sector_count;
-			fis[13] = ccb->ataio.cmd.sector_count_exp;
+			fis[12] &= 0xf8;
+			fis[12] |= tag << 3;
 		}
+		fis[13] = ccb->ataio.cmd.sector_count_exp;
 		fis[15] = ATA_A_4BIT;
 		if (ccb->ataio.ata_flags & ATA_FLAG_AUX) {
 			fis[16] =  ccb->ataio.aux        & 0xff;