diff --git a/[refs] b/[refs]
index a6e2ba333c9f..910291eca2cf 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 6f9aa727433fe7647869c9b64ce2f7b5feac0052
+refs/heads/master: 7fea82ab1a74030f79a2adfac1af3d93b8638fc3
diff --git a/trunk/arch/ppc64/kernel/prom_init.c b/trunk/arch/ppc64/kernel/prom_init.c
index adcf972711fc..122283a1d39a 100644
--- a/trunk/arch/ppc64/kernel/prom_init.c
+++ b/trunk/arch/ppc64/kernel/prom_init.c
@@ -892,7 +892,10 @@ static void __init prom_init_mem(void)
 	if ( RELOC(of_platform) == PLATFORM_PSERIES_LPAR )
 		RELOC(alloc_top) = RELOC(rmo_top);
 	else
-		RELOC(alloc_top) = RELOC(rmo_top) = min(0x40000000ul, RELOC(ram_top));
+		/* Some RS64 machines have buggy firmware where claims up at 1GB
+		 * fails. Cap at 768MB as a workaround. Still plenty of room.
+		 */
+		RELOC(alloc_top) = RELOC(rmo_top) = min(0x30000000ul, RELOC(ram_top));
 
 	prom_printf("memory layout at init:\n");
 	prom_printf("  memory_limit : %x (16 MB aligned)\n", RELOC(prom_memory_limit));