diff --git a/hw/ide/cmd646.c b/hw/ide/cmd646.c
index 9d60590..07fcf4d 100644
--- a/hw/ide/cmd646.c
+++ b/hw/ide/cmd646.c
@@ -123,6 +123,9 @@ static void bmdma_writeb_common(PCIIDEState
*pci_dev, BMDMAState *bm,
     printf("bmdma: writeb 0x%02x : 0x%02x\n", addr, val);
 #endif
     switch(addr & 3) {
+    case 0:
+        bmdma_cmd_writeb(bm, addr, val);
+        break;
     case 1:
         pci_dev->dev.config[MRDMODE] =