diff --git a/kernel/src/memory/MemoryManager.cpp b/kernel/src/memory/MemoryManager.cpp
index a2a03927..a6add72c 100644
--- a/kernel/src/memory/MemoryManager.cpp
+++ b/kernel/src/memory/MemoryManager.cpp
@@ -69,7 +69,7 @@ namespace MemoryManager
         // We store our frame bitmap at the beginning of the largest free memory block.
         char* frame_bitmap_addr = (char*)largest_free.ptr;
 
-        usize frame_bitmap_size = physical_address_space_size / ARCH_PAGE_SIZE / 8 + 1;
+        usize frame_bitmap_size = get_blocks_from_size(physical_address_space_size / ARCH_PAGE_SIZE, 8UL);
 
         // This should never happen, unless memory is very fragmented. Usually there is always a very big block of
         // usable memory and then some tiny blocks around it.
@@ -96,7 +96,8 @@ namespace MemoryManager
             }
         }
 
-        lock_frames((u64)frame_bitmap_addr, frame_bitmap_size / ARCH_PAGE_SIZE + 1);
+        // Make sure that the physical frames used by the bitmap aren't handed out to anyone else.
+        lock_frames(largest_free.ptr, get_blocks_from_size(frame_bitmap_size, ARCH_PAGE_SIZE));
     }
 
     void init()