diff --git a/src/heap.c b/src/heap.c
index e2ad1466..ec2a793f 100644
--- a/src/heap.c
+++ b/src/heap.c
@@ -587,21 +587,19 @@ static bool mi_heap_print_json_visit(const mi_heap_t* heap, const mi_heap_area_t
     varg->area_count++;
     varg->block_count = 0;
     _mi_fprintf(varg->out, varg->out_arg, 
-                  "\"page\": %zu, \"start\": 0x%p, \"block_size\": %zu, \"used_size\": %zu,\n  \"reserved\": %zu, \"committed\": %zu,", 
+                  "\"page\": %zu, \"start\": 0x%p, \"block_size\": %zu, \"used_size\": %zu,\n  \"reserved\": %zu, \"committed\": %zu, \"blocks\": [\n", 
                   varg->area_count, area->blocks, area->block_size, area->used, area->reserved, area->committed);
-    _mi_fprintf(varg->out, varg->out_arg, " \"blocks\": [\n");
   }
   else {
-    _mi_fprintf(varg->out, varg->out_arg, varg->block_count==0 ? "   {" : "  ,{");
-    varg->block_count++;
     _mi_fprintf(varg->out, varg->out_arg, 
-                   "\"block\": 0x%p, \"valid\": %s, \"size\": %zu, \"usable_size\": %zu, \"allocated_size\": %zu,\n    ", 
-                   info->block, info->valid ? "true" : "false", info->size, info->usable_size, info->allocated_size);
+                   "%s\"block\": 0x%p, \"valid\": %s, \"size\": %zu, \"usable_size\": %zu, \"allocated_size\": %zu,\n    ", 
+                    (varg->block_count==0 ? "   {" : "  ,{"), info->block, info->valid ? "true" : "false", info->size, info->usable_size, info->allocated_size);
+    varg->block_count++;
     int lineno;
     const char* fname;
     void* ret = mi_source_unpack(info->source, &fname, &lineno);
     if (fname!=NULL) _mi_fprintf(varg->out, varg->out_arg, "\"source\": \"%s:%i\" }\n", fname, lineno);
-    else if (ret != NULL) _mi_fprintf(varg->out, varg->out_arg, "\"source\": \"(%p)\" }\n", ret);
+    else if (ret != NULL) _mi_fprintf(varg->out, varg->out_arg, "\"source\": \"0x%p\" }\n", ret);
     else _mi_fprintf(varg->out, varg->out_arg, "\"source\": \"\" }\n");
   }
   return true;
@@ -610,8 +608,7 @@ static bool mi_heap_print_json_visit(const mi_heap_t* heap, const mi_heap_area_t
 void mi_heap_print_json(mi_heap_t* heap, mi_output_fun* out, void* arg) {
   if (heap==NULL) heap = mi_heap_get_default();
   mi_print_json_t info = { 0, 0, out, arg };
-  _mi_fprintf(info.out, info.out_arg, "{ \"heap\": 0x%p, \"thread_id\": 0x%zx, \"page_count\": %zu, \"block_padding\": %zu", heap, heap->thread_id, heap->page_count, mi_extra_padding(heap) );
-  _mi_fprintf(info.out, info.out_arg, ", \"pages\": [\n");
+  _mi_fprintf(info.out, info.out_arg, "{ \"heap\": 0x%p, \"thread_id\": 0x%zx, \"page_count\": %zu, \"block_padding\": %zu, \"pages\": [\n", heap, heap->thread_id, heap->page_count, mi_extra_padding(heap) );
   mi_heap_visit_blocks(heap, true, &mi_heap_print_json_visit, &info);
   _mi_fprintf(info.out, info.out_arg, info.area_count==0 ? "]\n" : "  ] }\n] }\n");
 }
diff --git a/test/main-override-static.c b/test/main-override-static.c
index f72ef12c..0e54892c 100644
--- a/test/main-override-static.c
+++ b/test/main-override-static.c
@@ -24,9 +24,10 @@ int main() {
   // block_overflow1();
   // block_overflow2();
   // dangling_ptr_write();
+  void* (*fun_mimalloc)(size_t) = &mi_malloc;
 
   void* p1 = malloc(78);
-  void* p2 = malloc(24);
+  void* p2 = fun_mimalloc(24);
   free(p1);
   p1 = mi_malloc(8);
   //char* s = strdup("hello\n");