diff --git a/hw/apb_pci.c b/hw/apb_pci.c
index fb23397..cfa198c 100644
--- a/hw/apb_pci.c
+++ b/hw/apb_pci.c
@@ -323,7 +323,7 @@ static void apb_register_mem(void *opaque,
pcibus_t addr, pcibus_t size, int mm)

     APB_DPRINTF("%s: addr %" FMT_PCIBUS " size %" FMT_PCIBUS "mm %x\n",
                 __func__, addr, size, mm);
-    cpu_register_physical_memory(addr + d->mem_base, size, mm);
+    cpu_register_physical_memory(addr + d->mem_base, size, mm | IO_MEM_BSWAP);
 }