diff --git a/hw/serial.c b/hw/serial.c
index 48a5eb62b9..0ccc499285 100644
--- a/hw/serial.c
+++ b/hw/serial.c
@@ -306,7 +306,7 @@ static void serial_ioport_write(void *opaque, hwaddr addr, uint64_t val,
     SerialState *s = opaque;
 
     addr &= 7;
-    DPRINTF("write addr=0x%02x val=0x%02x\n", addr, val);
+    DPRINTF("write addr=0x%" HWADDR_PRIx " val=0x%" PRIx64 "\n", addr, val);
     switch(addr) {
     default:
     case 0:
@@ -527,7 +527,7 @@ static uint64_t serial_ioport_read(void *opaque, hwaddr addr, unsigned size)
         ret = s->scr;
         break;
     }
-    DPRINTF("read addr=0x%02x val=0x%02x\n", addr, ret);
+    DPRINTF("read addr=0x%" HWADDR_PRIx " val=0x%02x\n", addr, ret);
     return ret;
 }