diff --git a/entry.sh b/entry.sh
index 484ff88..bae631c 100755
--- a/entry.sh
+++ b/entry.sh
@@ -61,7 +61,7 @@ function first_stage(){
 	LVM_SIZE=$(dev_size /dev/mapper/cryptlvm)
 	
 	SWAP_SIZE=$(($(mem_size)/1024/1024))
-	ROOT_SIZE=$(($LVM_SIZE/1024/1024-SWAP_SIZE))
+	ROOT_SIZE=$(($LVM_SIZE/1024/1024-$SWAP_SIZE-512))
 	
 	echo lvcreate /dev/vg0 --name=root --size=${ROOT_SIZE}M
 	lvcreate /dev/vg0 --name=root --size=${ROOT_SIZE}M