diff --git a/grub-core/kern/efi/mm.c b/grub-core/kern/efi/mm.c
index e460b072e6..150e412ee7 100644
--- a/grub-core/kern/efi/mm.c
+++ b/grub-core/kern/efi/mm.c
@@ -737,10 +737,10 @@ grub_efi_mm_init (void)
   filtered_memory_map_end = filter_memory_map (memory_map, filtered_memory_map,
 					       desc_size, memory_map_end);
 
-  /* By default, request a quarter of the available memory.  */
+  /* By default, request three quarters of the available memory.  */
   total_pages = get_total_pages (filtered_memory_map, desc_size,
 				 filtered_memory_map_end);
-  required_pages = (total_pages >> 2);
+  required_pages = (total_pages >> 1) + (total_pages >> 2);
   if (required_pages < BYTES_TO_PAGES (MIN_HEAP_SIZE))
     required_pages = BYTES_TO_PAGES (MIN_HEAP_SIZE);
   else if (required_pages > BYTES_TO_PAGES (MAX_HEAP_SIZE))