diff --git a/hw/char/bcm2835_aux.c b/hw/char/bcm2835_aux.c
index 3f855196e3..a6fc1bf152 100644
--- a/hw/char/bcm2835_aux.c
+++ b/hw/char/bcm2835_aux.c
@@ -162,8 +162,9 @@ static void bcm2835_aux_write(void *opaque, hwaddr offset, uint64_t value,
     switch (offset) {
     case AUX_ENABLES:
         if (value != 1) {
-            qemu_log_mask(LOG_UNIMP, "%s: unsupported attempt to enable SPI "
-                          "or disable UART\n", __func__);
+            qemu_log_mask(LOG_UNIMP, "%s: unsupported attempt to enable SPI"
+                                     " or disable UART: 0x%"PRIx64"\n",
+                          __func__, value);
         }
         break;
 
diff --git a/hw/dma/bcm2835_dma.c b/hw/dma/bcm2835_dma.c
index 192bd377a0..6acc2b644e 100644
--- a/hw/dma/bcm2835_dma.c
+++ b/hw/dma/bcm2835_dma.c
@@ -180,7 +180,7 @@ static uint64_t bcm2835_dma_read(BCM2835DMAState *s, hwaddr offset,
         res = ch->debug;
         break;
     default:
-        qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %"HWADDR_PRIx"\n",
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset 0x%"HWADDR_PRIx"\n",
                       __func__, offset);
         break;
     }
@@ -228,7 +228,7 @@ static void bcm2835_dma_write(BCM2835DMAState *s, hwaddr offset,
         ch->debug = value;
         break;
     default:
-        qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %"HWADDR_PRIx"\n",
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset 0x%"HWADDR_PRIx"\n",
                       __func__, offset);
         break;
     }
@@ -247,7 +247,7 @@ static uint64_t bcm2835_dma0_read(void *opaque, hwaddr offset, unsigned size)
         case BCM2708_DMA_ENABLE:
             return s->enable;
         default:
-            qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %"HWADDR_PRIx"\n",
+            qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset 0x%"HWADDR_PRIx"\n",
                           __func__, offset);
             return 0;
         }
@@ -274,7 +274,7 @@ static void bcm2835_dma0_write(void *opaque, hwaddr offset, uint64_t value,
             s->enable = (value & 0xffff);
             break;
         default:
-            qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %"HWADDR_PRIx"\n",
+            qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset 0x%"HWADDR_PRIx"\n",
                           __func__, offset);
         }
     }
diff --git a/hw/intc/bcm2836_control.c b/hw/intc/bcm2836_control.c
index 04229b8a17..61f884ff9e 100644
--- a/hw/intc/bcm2836_control.c
+++ b/hw/intc/bcm2836_control.c
@@ -264,7 +264,7 @@ static uint64_t bcm2836_control_read(void *opaque, hwaddr offset, unsigned size)
     } else if (offset >= REG_MBOX0_RDCLR && offset < REG_LIMIT) {
         return s->mailboxes[(offset - REG_MBOX0_RDCLR) >> 2];
     } else {
-        qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %"HWADDR_PRIx"\n",
+        qemu_log_mask(LOG_UNIMP, "%s: Unsupported offset 0x%"HWADDR_PRIx"\n",
                       __func__, offset);
         return 0;
     }
@@ -293,8 +293,9 @@ static void bcm2836_control_write(void *opaque, hwaddr offset,
     } else if (offset >= REG_MBOX0_RDCLR && offset < REG_LIMIT) {
         s->mailboxes[(offset - REG_MBOX0_RDCLR) >> 2] &= ~val;
     } else {
-        qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %"HWADDR_PRIx"\n",
-                      __func__, offset);
+        qemu_log_mask(LOG_UNIMP, "%s: Unsupported offset 0x%"HWADDR_PRIx
+                                 " value 0x%"PRIx64"\n",
+                      __func__, offset, val);
         return;
     }
 
diff --git a/hw/misc/bcm2835_mbox.c b/hw/misc/bcm2835_mbox.c
index 79bad11631..7690b9afaf 100644
--- a/hw/misc/bcm2835_mbox.c
+++ b/hw/misc/bcm2835_mbox.c
@@ -176,7 +176,7 @@ static uint64_t bcm2835_mbox_read(void *opaque, hwaddr offset, unsigned size)
         break;
 
     default:
-        qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %"HWADDR_PRIx"\n",
+        qemu_log_mask(LOG_UNIMP, "%s: Unsupported offset 0x%"HWADDR_PRIx"\n",
                       __func__, offset);
         return 0;
     }
@@ -228,8 +228,9 @@ static void bcm2835_mbox_write(void *opaque, hwaddr offset,
         break;
 
     default:
-        qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %"HWADDR_PRIx"\n",
-                      __func__, offset);
+        qemu_log_mask(LOG_UNIMP, "%s: Unsupported offset 0x%"HWADDR_PRIx
+                                 " value 0x%"PRIx64"\n",
+                      __func__, offset, value);
         return;
     }
 
diff --git a/hw/misc/bcm2835_property.c b/hw/misc/bcm2835_property.c
index d8eb28f267..ab66d3572e 100644
--- a/hw/misc/bcm2835_property.c
+++ b/hw/misc/bcm2835_property.c
@@ -56,7 +56,8 @@ static void bcm2835_property_mbox_push(BCM2835PropertyState *s, uint32_t value)
             break;
         case 0x00010001: /* Get board model */
             qemu_log_mask(LOG_UNIMP,
-                          "bcm2835_property: %x get board model NYI\n", tag);
+                          "bcm2835_property: 0x%08x get board model NYI\n",
+                          tag);
             /* FIXME returning uninitialized memory */
             resplen = 4;
             break;
@@ -70,7 +71,8 @@ static void bcm2835_property_mbox_push(BCM2835PropertyState *s, uint32_t value)
             break;
         case 0x00010004: /* Get board serial */
             qemu_log_mask(LOG_UNIMP,
-                          "bcm2835_property: %x get board serial NYI\n", tag);
+                          "bcm2835_property: 0x%08x get board serial NYI\n",
+                          tag);
             /* FIXME returning uninitialized memory */
             resplen = 8;
             break;
@@ -106,7 +108,8 @@ static void bcm2835_property_mbox_push(BCM2835PropertyState *s, uint32_t value)
 
         case 0x00038001: /* Set clock state */
             qemu_log_mask(LOG_UNIMP,
-                          "bcm2835_property: %x set clock state NYI\n", tag);
+                          "bcm2835_property: 0x%08x set clock state NYI\n",
+                          tag);
             resplen = 8;
             break;
 
@@ -139,7 +142,8 @@ static void bcm2835_property_mbox_push(BCM2835PropertyState *s, uint32_t value)
         case 0x00038004: /* Set max clock rate */
         case 0x00038007: /* Set min clock rate */
             qemu_log_mask(LOG_UNIMP,
-                          "bcm2835_property: %x set clock rates NYI\n", tag);
+                          "bcm2835_property: 0x%08x set clock rate NYI\n",
+                          tag);
             resplen = 8;
             break;
 
@@ -284,8 +288,8 @@ static void bcm2835_property_mbox_push(BCM2835PropertyState *s, uint32_t value)
             break;
 
         default:
-            qemu_log_mask(LOG_GUEST_ERROR,
-                          "bcm2835_property: unhandled tag %08x\n", tag);
+            qemu_log_mask(LOG_UNIMP,
+                          "bcm2835_property: unhandled tag 0x%08x\n", tag);
             break;
         }
 
