diff --git a/sys/powerpc/powermac/uninorth.c b/sys/powerpc/powermac/uninorth.c
index e9ab291e33f..748148e7806 100644
--- a/sys/powerpc/powermac/uninorth.c
+++ b/sys/powerpc/powermac/uninorth.c
@@ -264,6 +264,7 @@ unin_chip_attach(device_t dev)
 	phandle_t  child;
 	phandle_t  iparent;
 	device_t   cdev;
+	cell_t     acells, scells;
 	char compat[32];
 	char name[32];
 	u_int irq, reg[3];
@@ -275,12 +276,21 @@ unin_chip_attach(device_t dev)
 	if (OF_getprop(root, "reg", reg, sizeof(reg)) < 8)
 		return (ENXIO);
 
-	if (strcmp(ofw_bus_get_name(dev), "u3") == 0
-	    || strcmp(ofw_bus_get_name(dev), "u4") == 0)
-		i = 1; /* #address-cells lies */
+	acells = scells = 1;
+	OF_getprop(OF_parent(root), "#address-cells", &acells, sizeof(acells));
+	OF_getprop(OF_parent(root), "#size-cells", &scells, sizeof(scells));
 
-	sc->sc_physaddr = reg[i];
-	sc->sc_size = reg[i+1];
+	i = 0;
+	sc->sc_physaddr = reg[i++];
+	if (acells == 2) {
+		sc->sc_physaddr <<= 32;
+		sc->sc_physaddr |= reg[i++];
+	}
+	sc->sc_size = reg[i++];
+	if (scells == 2) {
+		sc->sc_size <<= 32;
+		sc->sc_size |= reg[i++];
+	}
 
 	sc->sc_mem_rman.rm_type = RMAN_ARRAY;
 	sc->sc_mem_rman.rm_descr = "UniNorth Device Memory";
diff --git a/sys/powerpc/powermac/uninorthvar.h b/sys/powerpc/powermac/uninorthvar.h
index 43aa01d0e00..aa834f6a1e8 100644
--- a/sys/powerpc/powermac/uninorthvar.h
+++ b/sys/powerpc/powermac/uninorthvar.h
@@ -38,9 +38,9 @@ struct uninorth_softc {
 };
 
 struct unin_chip_softc {
-	u_int32_t		sc_physaddr;
+	uint64_t		sc_physaddr;
+	uint64_t		sc_size;
 	vm_offset_t		sc_addr;
-	u_int32_t		sc_size;
 	struct rman  		sc_mem_rman;
 	int			sc_version;
 };