diff --git a/hw/sparc/sun4m.c b/hw/sparc/sun4m.c
index d981de1841..3c29b68e67 100644
--- a/hw/sparc/sun4m.c
+++ b/hw/sparc/sun4m.c
@@ -1035,7 +1035,17 @@ static void sun4m_hw_init(const struct sun4m_hwdef *hwdef,
         ecc_init(hwdef->ecc_base, slavio_irq[28],
                  hwdef->ecc_version);
 
-    fw_cfg = fw_cfg_init_mem(CFG_ADDR, CFG_ADDR + 2);
+    dev = qdev_create(NULL, TYPE_FW_CFG_MEM);
+    fw_cfg = FW_CFG(dev);
+    qdev_prop_set_uint32(dev, "data_width", 1);
+    qdev_prop_set_bit(dev, "dma_enabled", false);
+    object_property_add_child(OBJECT(qdev_get_machine()), TYPE_FW_CFG,
+                              OBJECT(fw_cfg), NULL);
+    qdev_init_nofail(dev);
+    s = SYS_BUS_DEVICE(dev);
+    sysbus_mmio_map(s, 0, CFG_ADDR);
+    sysbus_mmio_map(s, 1, CFG_ADDR + 2);
+
     fw_cfg_add_i16(fw_cfg, FW_CFG_NB_CPUS, (uint16_t)smp_cpus);
     fw_cfg_add_i16(fw_cfg, FW_CFG_MAX_CPUS, (uint16_t)max_cpus);
     fw_cfg_add_i64(fw_cfg, FW_CFG_RAM_SIZE, (uint64_t)ram_size);