Index: linux-2.6.12.3/arch/ppc64/boot/main.c
===================================================================
--- linux-2.6.12.3.orig/arch/ppc64/boot/main.c
+++ linux-2.6.12.3/arch/ppc64/boot/main.c
@@ -22,7 +22,7 @@
 extern void printf(const char *fmt, ...);
 extern int sprintf(char *buf, const char *fmt, ...);
 void gunzip(void *, int, unsigned char *, int *);
-void *claim(unsigned int, unsigned int, unsigned int);
+void *claim(unsigned long, unsigned long, unsigned long);
 void flush_cache(void *, unsigned long);
 void pause(void);
 extern void exit(void);
@@ -31,9 +31,8 @@
 void *memmove(void *dest, const void *src, unsigned long n);
 void *memcpy(void *dest, const void *src, unsigned long n);
 
-/* Value picked to match that used by yaboot */
-#define PROG_START	0x01400000
-#define RAM_END		(256<<20) // Fixme: use OF */
+#define	ONE_MB		0x100000
+#define RAM_END		(512<<20) // Fixme: use OF */
 
 char *avail_ram;
 char *begin_avail, *end_avail;
@@ -75,13 +74,13 @@
 
 #define DEBUG
 
-static unsigned long claim_base = PROG_START;
+static unsigned long claim_base;
 
 static unsigned long try_claim(unsigned long size)
 {
 	unsigned long addr = 0;
 
-	for(; claim_base < RAM_END; claim_base += 0x100000) {
+	for(; claim_base < RAM_END; claim_base += ONE_MB) {
 #ifdef DEBUG
 		printf("    trying: 0x%08lx\n\r", claim_base);
 #endif
@@ -112,7 +111,23 @@
 	if (getprop(chosen_handle, "stdin", &stdin, sizeof(stdin)) != 4)
 		exit();
 
-	printf("zImage starting: loaded at 0x%x\n\r", (unsigned)_start);
+	printf("zImage starting: loaded at 0x%lx\n\r", (unsigned long)_start);
+
+	/*
+	 * The first available claim_base must be "out of the way" -
+	 * well above _start + kernel_size + initrd + overhead.
+	 */
+
+	claim_base = ((unsigned long) _start) +
+				((unsigned long) vmlinux_filesize) +
+				(unsigned long)(_initrd_end - _initrd_start) +
+				ONE_MB;
+
+	/*
+	 * Now round up the claim_base to a nice 1 MB boundary.
+	 */
+
+	claim_base = ((claim_base + ONE_MB - 1) / ONE_MB) * ONE_MB;
 
 	/*
 	 * Now we try to claim some memory for the kernel itself
@@ -122,7 +137,7 @@
 	 * size... In practice we add 1Mb, that is enough, but we should really
 	 * consider fixing the Makefile to put a _raw_ kernel in there !
 	 */
-	vmlinux_memsize += 0x100000;
+	vmlinux_memsize += ONE_MB;
 	printf("Allocating 0x%lx bytes for kernel ...\n\r", vmlinux_memsize);
 	vmlinux.addr = try_claim(vmlinux_memsize);
 	if (vmlinux.addr == 0) {