diff --git a/src/arena-meta.c b/src/arena-meta.c
index ff50ea60..530e42cb 100644
--- a/src/arena-meta.c
+++ b/src/arena-meta.c
@@ -25,9 +25,9 @@ terms of the MIT license. A copy of the license can be found in the file
 #define MI_META_PAGE_SIZE         MI_ARENA_SLICE_SIZE
 #define MI_META_PAGE_ALIGN        MI_ARENA_SLICE_ALIGN
 
-#define MI_META_BLOCK_SIZE        (128)                       // large enough such that META_MAX_SIZE > 4k (even on 32-bit)
+#define MI_META_BLOCK_SIZE        (128)                       // large enough such that META_MAX_SIZE >= 4k (even on 32-bit)
 #define MI_META_BLOCK_ALIGN       MI_META_BLOCK_SIZE
-#define MI_META_BLOCKS_PER_PAGE   (MI_ARENA_SLICE_SIZE / MI_META_BLOCK_SIZE)  // 1024
+#define MI_META_BLOCKS_PER_PAGE   (MI_META_PAGE_SIZE / MI_META_BLOCK_SIZE)  // 512
 #define MI_META_MAX_SIZE          (MI_BCHUNK_SIZE * MI_META_BLOCK_SIZE)
 
 typedef struct mi_meta_page_s  {
@@ -150,7 +150,7 @@ mi_decl_noinline void _mi_meta_free(void* p, size_t size, mi_memid_t memid) {
     const size_t block_idx   = memid.mem.meta.block_index;
     mi_meta_page_t* mpage = (mi_meta_page_t*)memid.mem.meta.meta_page; 
     mi_assert_internal(mi_meta_page_of_ptr(p,NULL) == mpage);
-    mi_assert_internal(block_idx + block_count < MI_META_BLOCKS_PER_PAGE);
+    mi_assert_internal(block_idx + block_count <= MI_META_BLOCKS_PER_PAGE);
     mi_assert_internal(mi_bbitmap_is_clearN(&mpage->blocks_free, block_idx, block_count));
     // we zero on free (and on the initial page allocation) so we don't need a "dirty" map
     _mi_memzero_aligned(mi_meta_block_start(mpage, block_idx), block_count*MI_META_BLOCK_SIZE);