diff --git a/hw/dma/bcm2835_dma.c b/hw/dma/bcm2835_dma.c
index d07459de2d..b842aef4b7 100644
--- a/hw/dma/bcm2835_dma.c
+++ b/hw/dma/bcm2835_dma.c
@@ -86,6 +86,23 @@ static void bcm2835_dma_update(BCM2835DMAState *s, unsigned c)
         }
         xlen_td = xlen;
 
+        if (ch->ti & BCM2708_DMA_D_WIDTH) {
+            qemu_log_mask(LOG_UNIMP, "%s: 128bit transfers not yet supported", __func__);
+            ch->cs |= BCM2708_DMA_ERR;
+            break;
+        }
+
+        /*
+         * Datasheet implies 32bit or 128bit transfers only
+         *
+         * TODO: test on real HW and report back.
+         */
+        if (xlen & 0x3) {
+            qemu_log_mask(LOG_GUEST_ERROR, "%s: bad transfer size\n", __func__);
+            ch->cs |= BCM2708_DMA_ERR;
+            break;
+        }
+
         while (ylen != 0) {
             /* Normal transfer mode */
             while (xlen != 0) {