Index: stand/efi/loader/copy.c
===================================================================
--- stand/efi/loader/copy.c
+++ stand/efi/loader/copy.c
@@ -176,7 +176,11 @@
 #endif /* __i386__ || __amd64__ */
 
 #ifndef EFI_STAGING_SIZE
-#define	EFI_STAGING_SIZE	64
+  #if defined(__amd64__)
+    #define	EFI_STAGING_SIZE	150
+  #else
+    #define	EFI_STAGING_SIZE	64
+  #endif
 #endif
 
 EFI_PHYSICAL_ADDRESS	staging, staging_end;