diff --git a/hw/pc.c b/hw/pc.c
index 8c1b7ea..b5dabdd 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -1075,7 +1075,7 @@ static void pc_init1(ram_addr_t ram_size,
         isa_bios_size = 128 * 1024;
     cpu_register_physical_memory(0x100000 - isa_bios_size,
                                  isa_bios_size,
-                                 (bios_offset + bios_size - isa_bios_size) | IO_MEM_ROM);
+                                 (bios_offset + bios_size - isa_bios_size));