diff --git a/mm/memory.c b/mm/memory.c
index 7168e8e9..1e352bf1 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -33,7 +33,7 @@
  * 0 => free
  * 1 => occupied
  */
-static uint8_t	 	bitmap[BITMAP_SIZE];
+static uint8_t	 	bitmap[BITMAP_SIZE] = {[0 ... BITMAP_SIZE-1] = 0xFF};
 static spinlock_t	bitmap_lock = SPINLOCK_INIT;
 static size_t		alloc_start;
 atomic_int32_t		total_pages = ATOMIC_INIT(0);
@@ -85,18 +85,20 @@ int mmu_init(void)
 	size_t addr;
 
 	/* set whole address space as occupied */
-	memset(bitmap, 0xFF, sizeof(uint8_t)*BITMAP_SIZE);
+	// array is already initialized (see declaration)
+	//memset(bitmap, 0xFF, sizeof(uint8_t)*BITMAP_SIZE);
 
 #ifdef CONFIG_MULTIBOOT
 	if (mb_info && (mb_info->flags & (1 << (6)))) {
 		multiboot_memory_map_t* mmap = (multiboot_memory_map_t*) mb_info->mmap_addr;
 		multiboot_memory_map_t* mmap_end = (void*) ((size_t) mb_info->mmap_addr + mb_info->mmap_length);
+		size_t end_addr;
 
 		while (mmap < mmap_end) {
 			if (mmap->type == MULTIBOOT_MEMORY_AVAILABLE) {
 				/* set the available memory as "unused" */
-				size_t end_addr = addr + mmap->len;
-        			addr = mmap->addr;
+				addr = mmap->addr;
+				end_addr = addr + mmap->len;
  
 				while (addr < end_addr) {
 					page_clear_mark(addr / PAGE_SIZE);