diff --git a/arch/x86/include/asm/multiboot.h b/arch/x86/include/asm/multiboot.h
index 9d41ec0e..a191631d 100644
--- a/arch/x86/include/asm/multiboot.h
+++ b/arch/x86/include/asm/multiboot.h
@@ -28,6 +28,11 @@
  * which specifies an interface between a boot loader and a operating system
  */
 
+/* are there modules to do something with? */
+#define MULTIBOOT_INFO_MODS		0x00000008
+/* is there a full memory map? */
+#define MULTIBOOT_INFO_MEM_MAP		0x00000040
+
 typedef uint16_t multiboot_uint16_t;
 typedef uint32_t multiboot_uint32_t;
 typedef uint64_t multiboot_uint64_t;
diff --git a/fs/initrd.c b/fs/initrd.c
index 99b19669..5349b7bb 100644
--- a/fs/initrd.c
+++ b/fs/initrd.c
@@ -218,7 +218,7 @@ int initrd_init(void)
 	uint32_t mods_count = 0;
 	multiboot_module_t* mmodule = NULL;
 
-	if (mb_info && (mb_info->flags & (1 << 3))) {
+	if (mb_info && (mb_info->flags & MULTIBOOT_INFO_MODS)) {
                 mmodule = (multiboot_module_t*) mb_info->mods_addr;
 		mods_count = mb_info->mods_count;
         }
diff --git a/mm/memory.c b/mm/memory.c
index fbefd461..e33b5202 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -94,7 +94,7 @@ int mmu_init(void)
 	size_t addr, end_addr;
 
 #ifdef CONFIG_MULTIBOOT
-	if (mb_info && (mb_info->flags & (1 << 6))) {
+	if (mb_info && (mb_info->flags & MULTIBOOT_INFO_MEM_MAP)) {
 		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);
 
@@ -124,7 +124,7 @@ int mmu_init(void)
 	 * Modules like the init ram disk are already loaded.
 	 * Therefore, we set these pages as used.
 	 */
-	if (mb_info && (mb_info->flags & (1 << 3))) {
+	if (mb_info && (mb_info->flags & MULTIBOOT_INFO_MODS)) {
 		multiboot_module_t* mmodule = (multiboot_module_t*) mb_info->mods_addr;
 
 		for(i=0; i<mb_info->mods_count; i++, mmodule++) {