diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
index efd07ac8041e..1027a60a9b90 100644
--- a/hw/ide/ahci.c
+++ b/hw/ide/ahci.c
@@ -1086,8 +1086,11 @@ static void process_ncq_command(AHCIState *s, int port, uint8_t *cmd_fis,
         DPRINTF(port, "Warn: Unsupported attempt to use Rebuild Assist\n");
     }
 
-    ncq_tfs->sector_count = ((uint16_t)ncq_fis->sector_count_high << 8) |
-                                ncq_fis->sector_count_low;
+    ncq_tfs->sector_count = ((ncq_fis->sector_count_high << 8) |
+                             ncq_fis->sector_count_low);
+    if (!ncq_tfs->sector_count) {
+        ncq_tfs->sector_count = 0x10000;
+    }
     size = ncq_tfs->sector_count * 512;
     ahci_populate_sglist(ad, &ncq_tfs->sglist, size, 0);
 
diff --git a/hw/ide/ahci.h b/hw/ide/ahci.h
index c728e3a07d3b..9090d3d882db 100644
--- a/hw/ide/ahci.h
+++ b/hw/ide/ahci.h
@@ -256,7 +256,7 @@ typedef struct NCQTransferState {
     BlockAIOCB *aiocb;
     QEMUSGList sglist;
     BlockAcctCookie acct;
-    uint16_t sector_count;
+    uint32_t sector_count;
     uint64_t lba;
     uint8_t tag;
     uint8_t cmd;