diff --git a/hw/sun4u.c b/hw/sun4u.c
index 9d2a7f59e36112d194ca710a410a2ed3cb5a0fef..5f154390c675a218fcd28dcd76b5ed6b38638620 100644
--- a/hw/sun4u.c
+++ b/hw/sun4u.c
@@ -32,6 +32,7 @@
 #include "boards.h"
 #include "firmware_abi.h"
 #include "fw_cfg.h"
+#include "sysbus.h"
 
 //#define DEBUG_IRQ
 
@@ -342,6 +343,64 @@ static void pci_ebus_register(void)
 
 device_init(pci_ebus_register);
 
+/* Boot PROM (OpenBIOS) */
+static void prom_init(target_phys_addr_t addr, const char *bios_name)
+{
+    DeviceState *dev;
+    SysBusDevice *s;
+    char *filename;
+    int ret;
+
+    dev = qdev_create(NULL, "openprom");
+    qdev_init(dev);
+    s = sysbus_from_qdev(dev);
+
+    sysbus_mmio_map(s, 0, addr);
+
+    /* load boot prom */
+    if (bios_name == NULL) {
+        bios_name = PROM_FILENAME;
+    }
+    filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, bios_name);
+    if (filename) {
+        ret = load_elf(filename, addr - PROM_VADDR, NULL, NULL, NULL);
+        if (ret < 0 || ret > PROM_SIZE_MAX) {
+            ret = load_image_targphys(filename, addr, PROM_SIZE_MAX);
+        }
+        qemu_free(filename);
+    } else {
+        ret = -1;
+    }
+    if (ret < 0 || ret > PROM_SIZE_MAX) {
+        fprintf(stderr, "qemu: could not load prom '%s'\n", bios_name);
+        exit(1);
+    }
+}
+
+static void prom_init1(SysBusDevice *dev)
+{
+    ram_addr_t prom_offset;
+
+    prom_offset = qemu_ram_alloc(PROM_SIZE_MAX);
+    sysbus_init_mmio(dev, PROM_SIZE_MAX, prom_offset | IO_MEM_ROM);
+}
+
+static SysBusDeviceInfo prom_info = {
+    .init = prom_init1,
+    .qdev.name  = "openprom",
+    .qdev.size  = sizeof(SysBusDevice),
+    .qdev.props = (Property[]) {
+        {/* end of property list */}
+    }
+};
+
+static void prom_register_devices(void)
+{
+    sysbus_register_withprop(&prom_info);
+}
+
+device_init(prom_register_devices);
+
 static void sun4uv_init(ram_addr_t RAM_size,
                         const char *boot_devices,
                         const char *kernel_filename, const char *kernel_cmdline,
@@ -349,11 +408,10 @@ static void sun4uv_init(ram_addr_t RAM_size,
                         const struct hwdef *hwdef)
 {
     CPUState *env;
-    char *filename;
     m48t59_t *nvram;
-    int ret, linux_boot;
+    int linux_boot;
     unsigned int i;
-    ram_addr_t ram_offset, prom_offset;
+    ram_addr_t ram_offset;
     long initrd_size, kernel_size;
     PCIBus *pci_bus, *pci_bus2, *pci_bus3;
     QEMUBH *bh;
@@ -400,32 +458,7 @@ static void sun4uv_init(ram_addr_t RAM_size,
     ram_offset = qemu_ram_alloc(RAM_size);
     cpu_register_physical_memory(0, RAM_size, ram_offset);
 
-    prom_offset = qemu_ram_alloc(PROM_SIZE_MAX);
-    cpu_register_physical_memory(hwdef->prom_addr,
-                                 (PROM_SIZE_MAX + TARGET_PAGE_SIZE) &
-                                 TARGET_PAGE_MASK,
-                                 prom_offset | IO_MEM_ROM);
-
-    if (bios_name == NULL)
-        bios_name = PROM_FILENAME;
-    filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, bios_name);
-    if (filename) {
-        ret = load_elf(filename, hwdef->prom_addr - PROM_VADDR,
-                       NULL, NULL, NULL);
-        if (ret < 0) {
-            ret = load_image_targphys(filename, hwdef->prom_addr,
-                                      (PROM_SIZE_MAX + TARGET_PAGE_SIZE) &
-                                  TARGET_PAGE_MASK);
-        }
-        qemu_free(filename);
-    } else {
-        ret = -1;
-    }
-    if (ret < 0) {
-        fprintf(stderr, "qemu: could not load prom '%s'\n",
-                bios_name);
-        exit(1);
-    }
+    prom_init(hwdef->prom_addr, bios_name);
 
     kernel_size = 0;
     initrd_size = 0;