Index: sys/powerpc/ofw/ofw_machdep.c
===================================================================
--- sys/powerpc/ofw/ofw_machdep.c
+++ sys/powerpc/ofw/ofw_machdep.c
@@ -294,19 +294,36 @@
 excise_initrd_region(struct mem_region *avail, int asz)
 {
 	phandle_t chosen;
+	pcell_t cell[2];
 	uint64_t start, end;
 	ssize_t size;
 	struct mem_region initrdmap[1];
 
 	chosen = OF_finddevice("/chosen");
-	size = OF_getprop(chosen, "linux,initrd-start", &start, sizeof(start));
+
+	size = OF_getencprop(chosen, "linux,initrd-start", cell, sizeof(cell));
 	if (size <= 0)
 		return (asz);
 
-	size = OF_getprop(chosen, "linux,initrd-end", &end, sizeof(end));
+	KASSERT(size == 4 || size == 8, ("linux,initrd-start, when present, must be either 4 or 8 bytes long"));
+	if (size == 4)
+		start = cell[0];
+	else
+		start = (uint64_t)cell[0] << 32 | cell[1];
+
+	size = OF_getencprop(chosen, "linux,initrd-end", cell, sizeof(cell));
 	if (size <= 0)
 		return (asz);
 
+	KASSERT(size == 4 || size == 8, ("linux,initrd-end, when present, must be either 4 or 8 bytes long"));
+	if (size == 4)
+		end = cell[0];
+	else
+		end = (uint64_t)cell[0] << 32 | cell[1];
+
+	if (end <= start)
+		return (asz);
+
 	initrdmap[0].mr_start = start;
 	initrdmap[0].mr_size = end - start;