diff --git a/.cell/cell.toml b/.cell/cell.toml
index 5fe113a2..e948c577 100644
--- a/.cell/cell.toml
+++ b/.cell/cell.toml
@@ -1,6 +1,6 @@
 sdl_video = "main"
 [dependencies]
-extramath = "https://gitea.pockle.world/john/extramath@master"
+extramath = "gitea.pockle.world/john/extramath@master"
 [system]
 ar_timer = 60
 actor_memory = 0
@@ -16,4 +16,4 @@ main = true
 [actors.prosperon]
 main = true
 [actors.accio]
-main=true
\ No newline at end of file
+main = true
\ No newline at end of file
diff --git a/Makefile b/Makefile
index 7e8f815c..281e56e0 100755
--- a/Makefile
+++ b/Makefile
@@ -11,7 +11,7 @@ release: FORCE
 	meson install -C build_release
 
 sanitize: FORCE
-	meson setup -Db_sanitize=address -Db_sanitize=memory -Db_sanitize=leak -Db_sanitize=undefined build_sani
+	meson setup -Db_sanitize=address -Db_sanitize=memory -Db_sanitize=leak build_sani
 	meson install -C build_sani
 
 thread: FORCE
diff --git a/scripts/fd.c b/scripts/fd.c
index 9c59d176..6f38c583 100644
--- a/scripts/fd.c
+++ b/scripts/fd.c
@@ -223,10 +223,36 @@ JSC_SCALL(fd_mv,
     }
 )
 
+JSC_SCALL(fd_symlink,
+    if (argc < 2)
+        ret = JS_ThrowTypeError(js, "fd.symlink requires 2 arguments: target and link path");
+    else if (!JS_IsString(argv[1]))
+        ret = JS_ThrowTypeError(js, "second argument must be a string (link path)");
+    else {
+        const char *link_path = JS_ToCString(js, argv[1]);
+#ifdef _WIN32
+        if (!CreateSymbolicLinkA(link_path, str, SYMBOLIC_LINK_FLAG_DIRECTORY)) {
+             // Try file
+             if (!CreateSymbolicLinkA(link_path, str, 0)) {
+                 ret = JS_ThrowInternalError(js, "could not create symlink %s -> %s: %lu", link_path, str, GetLastError());
+             }
+        }
+#else
+        if (symlink(str, link_path) != 0)
+            ret = JS_ThrowInternalError(js, "could not create symlink %s -> %s: %s", link_path, str, strerror(errno));
+#endif
+        JS_FreeCString(js, link_path);
+    }
+)
+
 // Helper function for recursive removal
 static int remove_recursive(const char *path) {
     struct stat st;
+#ifdef _WIN32
     if (stat(path, &st) != 0)
+#else
+    if (lstat(path, &st) != 0)
+#endif
         return -1;
     
     if (S_ISDIR(st.st_mode)) {
@@ -565,6 +591,7 @@ static const JSCFunctionListEntry js_fd_funcs[] = {
     MIST_FUNC_DEF(fd, is_file, 1),
     MIST_FUNC_DEF(fd, is_dir, 1),
     MIST_FUNC_DEF(fd, enumerate, 2),
+    MIST_FUNC_DEF(fd, symlink, 2),
 };
 
 JSValue js_fd_use(JSContext *js) {
diff --git a/scripts/os.c b/scripts/os.c
index 940fef8b..10a45ddd 100644
--- a/scripts/os.c
+++ b/scripts/os.c
@@ -383,6 +383,7 @@ static JSValue js_os_dylib_symbol(JSContext *js, JSValue self, int argc, JSValue
       error_msg = dl_error;
     }
 #endif
+    return JS_ThrowReferenceError(js, "Failed to load symbol: %s", error_msg);
     return JS_NULL;
   }
 
@@ -390,6 +391,34 @@ static JSValue js_os_dylib_symbol(JSContext *js, JSValue self, int argc, JSValue
   return symbol(js);
 }
 
+static JSValue js_os_dylib_has_symbol(JSContext *js, JSValue self, int argc, JSValue *argv)
+{
+  if (argc < 2) {
+    return JS_ThrowTypeError(js, "dylib_has_symbol requires dylib object and symbol name");
+  }
+
+  void *handle = JS_GetOpaque(argv[0], js_dylib_class_id);
+  if (!handle) {
+    return JS_ThrowTypeError(js, "First argument must be a dylib object");
+  }
+
+  const char *symbol_name = JS_ToCString(js, argv[1]);
+  if (!symbol_name) {
+    return JS_ThrowTypeError(js, "symbol name must be a string");
+  }
+
+  void *symbol;
+#ifdef _WIN32
+  symbol = (void*)GetProcAddress((HMODULE)handle, symbol_name);
+#else
+  symbol = dlsym(handle, symbol_name);
+#endif
+
+  JS_FreeCString(js, symbol_name);
+
+  return JS_NewBool(js, symbol != NULL);
+}
+
 JSC_CCALL(os_print,
     size_t len;
     const char *str = JS_ToCStringLen(js, &len, argv[0]);
@@ -427,6 +456,33 @@ static JSValue js_os_load_internal(JSContext *js, JSValue self, int argc, JSValu
   return symbol(js);
 }
 
+static JSValue js_os_internal_exists(JSContext *js, JSValue self, int argc, JSValue *argv)
+{
+  void *handle;
+#ifdef _WIN32
+  handle = GetModuleHandle(NULL);
+#else
+  handle = dlopen(NULL, RTLD_LAZY);
+#endif
+  if (argc < 1)
+    return JS_ThrowTypeError(js, "internal_exists requires a symbol name");
+
+  const char *symbol_name = JS_ToCString(js, argv[0]);
+  if (!symbol_name)
+    return JS_ThrowTypeError(js, "symbol name must be a string");
+
+  void *symbol;
+#if defined(_WIN32)
+  symbol = (void*)GetProcAddress((HMODULE)handle, symbol_name);
+#else
+  symbol = dlsym(handle, symbol_name);
+#endif
+
+  JS_FreeCString(js, symbol_name);
+
+  return JS_NewBool(js, symbol != NULL);
+}
+
 #if defined(_WIN32)
 // ------- Windows: use BCryptGenRandom -------
 int randombytes(void *buf, size_t n) {
@@ -494,7 +550,9 @@ static const JSCFunctionListEntry js_os_funcs[] = {
   MIST_FUNC_DEF(os, sleep, 1),
   MIST_FUNC_DEF(os, dylib_open, 1),
   MIST_FUNC_DEF(os, dylib_symbol, 2),
+  MIST_FUNC_DEF(os, dylib_has_symbol, 2),
   MIST_FUNC_DEF(os, load_internal, 1),
+  MIST_FUNC_DEF(os, internal_exists, 1),
   MIST_FUNC_DEF(os, print, 1),
   MIST_FUNC_DEF(os, random, 0),
 };
diff --git a/scripts/replace.ce b/scripts/replace.ce
index 0408f680..96330f3f 100644
--- a/scripts/replace.ce
+++ b/scripts/replace.ce
@@ -1,49 +1,29 @@
-// cell replace <alias> <path> - Add or update a replace directive for a dependency
+// cell replace [package] [path]
+// replace a package with a local directory
 
-var fd = use('fd')
 var shop = use('shop')
 
 if (args.length < 2) {
-  log.console("Usage: cell replace <alias> <path>")
-  log.console("Examples:")
-  log.console("  cell replace prosperon ../prosperon")
-  log.console("  cell replace extramath ../my-fork-of-extramath")
-  $_.stop()
-  return
+    log.console("Usage: cell replace <package> <path>")
+    log.console("       cell replace <package> --remove")
+    $_.stop()
 }
 
-var alias = args[0]
+var pkg = args[0]
 var path = args[1]
 
-// Initialize shop if needed
-if (!fd.stat('.cell/cell.toml').isFile) {
-  log.console("No cell.toml found. Initializing...")
-  shop.init()
+if (path == '--remove') {
+    if (shop.remove_replacement(pkg)) {
+        log.console("Replacement removed.")
+    } else {
+        log.console("Failed to remove replacement.")
+    }
+} else {
+    if (shop.add_replacement(pkg, path)) {
+        log.console("Replacement added.")
+    } else {
+        log.console("Failed to add replacement.")
+    }
 }
 
-// Load current config
-var config = shop.load_config()
-if (!config) {
-  log.error("Failed to load cell.toml")
-  $_.stop()
-  return
-}
-
-// Check if the alias exists in dependencies
-if (!config.dependencies || !config.dependencies[alias]) {
-  log.console("Warning: '" + alias + "' is not in dependencies. Adding replace anyway.")
-}
-
-// Ensure replace section exists
-if (!config.replace) {
-  config.replace = {}
-}
-
-// Add or update the replace directive
-config.replace[alias] = path
-shop.save_config(config)
-
-log.console("Added replace directive: " + alias + " = " + path)
-log.console("Run 'cell build' to apply changes")
-
-$_.stop()
+$_.stop()
\ No newline at end of file
diff --git a/scripts/shop.cm b/scripts/shop.cm
index e2587e4c..7be64e92 100644
--- a/scripts/shop.cm
+++ b/scripts/shop.cm
@@ -348,11 +348,6 @@ Shop.get_module_dir = function(alias) {
     return null
   }
   
-  // Check if replaced
-  if (config.replace && config.replace[alias]) {
-    return config.replace[alias]
-  }
-
   var pkg = config.dependencies[alias]
   var parsed = Shop.parse_package(pkg)
   if (!parsed) return null
@@ -568,19 +563,19 @@ function resolve_locator(path, ext, ctx)
   return null;
 }
 
-function resolve_c_symbol(path, package_ctx)
+function resolve_c_symbol(path, package_context)
 {
-  var local_path = package_ctx ? package_ctx : 'local'
+  var local_path = package_context ? package_context : 'local'
   var local_sym_base = path.replace(/\//g, '_').replace(/-/g, '_').replace(/\./g, '_')
   var local
   
-  if (!package_ctx) {
+  if (!package_context) {
      local = `js_local_${local_sym_base}_use`
   } else {
      local = `js_${local_path.replace(/\//g, '_').replace(/-/g, '_').replace(/\./g, '_')}_${local_sym_base}_use`
   }
   
-  var build_dir = get_build_dir(package_ctx)
+  var build_dir = get_build_dir(package_context)
   var local_dl_name = build_dir + '/cellmod' + dylib_ext
   
   if (fd.is_file(local_dl_name)) {
@@ -588,19 +583,25 @@ function resolve_c_symbol(path, package_ctx)
       open_dls[local_dl_name] = os.dylib_open(local_dl_name);
     
     if (open_dls[local_dl_name]) {
-      var local_addr = os.dylib_symbol(open_dls[local_dl_name], local);
-      if (local_addr) return {symbol: local_addr, scope: SCOPE_LOCAL};
+      if (os.dylib_has_symbol(open_dls[local_dl_name], local))
+        return {
+          symbol: function() { return os.dylib_symbol(open_dls[local_dl_name], local); },
+          scope: SCOPE_LOCAL
+        };
     }
   }
 
   // Try static linking fallback
-  var static_local_addr = os.load_internal(local);
-  if (static_local_addr) return {symbol: static_local_addr, scope: SCOPE_LOCAL};
+  if (os.internal_exists(local))
+    return {
+      symbol: function() { return os.load_internal(local); }, 
+      scope: SCOPE_LOCAL
+    };
 
   // If 'path' has a package alias (e.g. 'prosperon/sprite'), try to resolve it
   var pkg_alias = get_import_package(path)
   if (pkg_alias) {
-      var canon_pkg = get_normalized_package(path, package_ctx)
+      var canon_pkg = get_normalized_package(path, package_context)
       if (canon_pkg) {
           var build_dir = get_build_dir(canon_pkg)
           var dl_path = build_dir + '/cellmod' + dylib_ext
@@ -613,20 +614,30 @@ function resolve_c_symbol(path, package_ctx)
           if (fd.is_file(dl_path)) {
               if (!open_dls[dl_path]) open_dls[dl_path] = os.dylib_open(dl_path)
               if (open_dls[dl_path]) {
-                  var addr = os.dylib_symbol(open_dls[dl_path], sym_name)
-                  if (addr) return {symbol: addr, scope: SCOPE_PACKAGE, package: canon_pkg}
+                  if (os.dylib_has_symbol(open_dls[dl_path], sym_name))
+                    return {
+                      symbol: function() { return os.dylib_symbol(open_dls[dl_path], sym_name) },
+                      scope: SCOPE_PACKAGE, 
+                      package: canon_pkg
+                    }
               }
           }
           
-          var static_package_addr = os.load_internal(sym_name);
-          if (static_package_addr)
-            return {symbol:static_package_addr, scope: SCOPE_PACKAGE, package: canon_pkg};
+          if (os.internal_exists(sym_name))
+            return {
+              symbol: function() { return os.load_internal(sym_name) }, 
+              scope: SCOPE_PACKAGE, 
+              package: canon_pkg
+            };
       }
   }
 
-  var core_addr = os.load_internal(`js_${path.replace(/\//g, '_')}_use`);
-  if (core_addr)
-    return {symbol:core_addr, scope: SCOPE_CORE};
+  var core_sym = `js_${path.replace(/\//g, '_')}_use`;
+  if (os.internal_exists(core_sym))
+    return {
+      symbol: function() { return os.load_internal(core_sym); }, 
+      scope: SCOPE_CORE
+    };
 
   return null
 }
@@ -650,11 +661,11 @@ Shop.use = function(path, package_context) {
     return use_cache[cache_key]
 
   if (c_resolve.scope < mod_resolve.scope)
-    use_cache[cache_key] = c_resolve.symbol
+    use_cache[cache_key] = c_resolve.symbol()
   else if (mod_resolve.scope < c_resolve.scope)
     use_cache[cache_key] = mod_resolve.symbol.call()
   else
-    use_cache[cache_key] = mod_resolve.symbol.call(c_resolve.symbol)
+    use_cache[cache_key] = mod_resolve.symbol.call(c_resolve.symbol())
 
   return use_cache[cache_key]
 }
@@ -671,23 +682,11 @@ function get_cache_path(pkg, commit) {
 }
 
 function rm_recursive(path) {
-  var st = fd.stat(path)
-  if (!st) return
-  
-  if (!st.isDirectory) {
-    fd.unlink(path)
-    return
+  try {
+    fd.rm(path)
+  } catch (e) {
+    log.error("Failed to remove " + path + ": " + e)
   }
-  
-  var list = fd.readdir(path)
-  if (list) {
-    for (var i = 0; i < list.length; i++) {
-      var item = list[i]
-      if (item == '.' || item == '..') continue
-      rm_recursive(path + "/" + item)
-    }
-  }
-  fd.rmdir(path)
 }
 
 function get_all_files(dir, prefix, results) {
@@ -745,9 +744,8 @@ function verify_zip_contents(zip, target_dir) {
   
   // Check for extra files
   var existing_files = get_all_files(target_dir)
-  for (var i = 0; i < existing_files.length; i++) {
+  for (var i = 0; i < existing_files.length; i++)
     if (!expected_files[existing_files[i]]) return false
-  }
   
   return true
 }
@@ -944,100 +942,76 @@ Shop.get = function(pkg, alias) {
   return true
 }
 
-// High-level: Update a specific package or all packages
-// Like `bun update` or `bun update <pkg>`
-Shop.update_all = function(alias) {
+Shop.fetch = function(package)
+{
+  
+}
+
+// High-level: Update a specific package
+// Like `bun update <pkg>`
+Shop.update = function(pkg) {
   var config = Shop.load_config()
-  if (!config || !config.dependencies) {
-    log.console("No dependencies to update.")
-    return
-  }
-  
   var lock = Shop.load_lock()
-  var queue = []
-  var processed = {}
   
-  // Initialize queue
-  if (alias) {
-    if (config.dependencies[alias]) {
-      queue.push(config.dependencies[alias])
-    } else {
-      log.error("Dependency not found: " + alias)
-      return
+  // Check if replaced
+  if (config.replace && config.replace[pkg]) {
+    log.console("Skipping update for replaced package " + pkg)
+    Shop.update(config.replace[pkg])
+    return false
+  }
+  
+  // Find existing lock info
+  var lock_info = lock[pkg]
+  var local_hash = lock_info ? lock_info.commit : null
+  
+  var api_url = Shop.get_api_url(pkg)
+  var remote_hash = null
+  
+  // Check for updates if possible
+  if (api_url) {
+    try {
+      var resp = http.fetch(api_url)
+      remote_hash = Shop.extract_commit_hash(pkg, text(resp))
+    } catch (e) {
+      log.console("Warning: Could not check for updates for " + pkg)
     }
+  }
+  
+  var target_hash = remote_hash
+  if (!target_hash) {
+    log.error("Could not resolve remote commit for " + pkg)
+    return false
+  }
+  
+  if (local_hash && remote_hash == local_hash) {
+    log.console(alias + " is already up to date.")
+    return true
+  }
+  
+  if (local_hash) {
+    log.console("Updating " + alias + " " + local_hash.substring(0,8) + " -> " + remote_hash.substring(0,8))
   } else {
-    for (var k in config.dependencies) {
-      queue.push(config.dependencies[k])
-    }
+    log.console("Installing " + alias + "...")
   }
   
-  while (queue.length > 0) {
-    var pkg = queue.shift()
-    if (processed[pkg]) continue
-    processed[pkg] = true
-    
-    // Find existing lock info
-    var lock_info = lock[pkg]
-    var local_hash = lock_info ? lock_info.commit : null
-    var local_zip_hash = lock_info ? lock_info.zip_hash : null
-    
-    var api_url = Shop.get_api_url(pkg)
-    var remote_hash = null
-    
-    // Check for updates if possible
-    if (api_url) {
-      try {
-        var resp = http.fetch(api_url)
-        remote_hash = Shop.extract_commit_hash(pkg, text(resp))
-      } catch (e) {
-        log.console("Warning: Could not check for updates for " + pkg)
-      }
-    }
-    
-    var target_hash = remote_hash || local_hash
-    if (!target_hash) {
-      log.error("Could not resolve commit for " + pkg)
-      continue
-    }
-    
-    var is_update = remote_hash && local_hash && (remote_hash != local_hash)
-    if (is_update) {
-      log.console("Updating " + pkg + " " + local_hash.substring(0,8) + " -> " + remote_hash.substring(0,8))
-    } else {
-      log.console("Checking " + pkg + "...")
-    }
-    
-    // Install/Verify
-    // If updating, we pass null as local_zip_hash to force fresh download/check
-    // If verifying, we pass local_zip_hash
-    var result = install_from_package(pkg, target_hash, is_update ? null : local_zip_hash)
-    
-    if (result) {
-      // Update lock
-      lock[pkg] = {
-        package: pkg,
-        commit: result.commit,
-        zip_hash: result.zip_hash,
-        updated: time.number()
-      }
-      
-      // Read package config to find dependencies
-      var parsed = Shop.parse_package(pkg)
-      var pkg_config = Shop.load_config(parsed.path)
-      
-      if (pkg_config && pkg_config.dependencies) {
-        for (var k in pkg_config.dependencies) {
-          var dep_pkg = pkg_config.dependencies[k]
-          if (!processed[dep_pkg]) {
-             queue.push(dep_pkg)
-          }
-        }
-      }
+  // Install with fresh download (no zip hash to force redownload)
+  var result = install_from_package(pkg, target_hash, null)
+  
+  if (result) {
+    // Update lock
+    lock[pkg] = {
+      package: pkg,
+      commit: result.commit,
+      zip_hash: result.zip_hash,
+      updated: time.number()
     }
+    Shop.save_lock(lock)
+    log.console("Updated " + alias + ".")
+    return true
   }
   
-  Shop.save_lock(lock)
-  log.console("Update complete.")
+  log.error("Failed to update " + alias)
+  return false
 }
 
 // High-level: Remove a package and clean up
@@ -1077,6 +1051,33 @@ Shop.remove = function(alias) {
   return true
 }
 
+Shop.add_replacement = function(alias, replacement) {
+  var config = Shop.load_config()
+  if (!config) config = {}
+  if (!config.replace) config.replace = {}
+  
+  config.replace[alias] = replacement
+  Shop.save_config(config)
+  
+  log.console("Added replacement: " + alias + " = " + replacement)
+  return true
+}
+
+Shop.remove_replacement = function(alias) {
+  var config = Shop.load_config()
+  if (!config || !config.replace || !config.replace[alias]) {
+      log.error("No replacement found for " + alias)
+      return false
+  }
+  
+  delete config.replace[alias]
+  Shop.save_config(config)
+ 
+  log.console("Removed replacement for " + alias)
+  log.console("Run 'cell update " + alias + "' to restore the package.")
+  return true
+}
+
 // Install all dependencies from config (like `bun install`)
 Shop.install_all = function() {
   Shop.init()
diff --git a/scripts/update.ce b/scripts/update.ce
index cbb4d4b6..f71ec2d8 100644
--- a/scripts/update.ce
+++ b/scripts/update.ce
@@ -4,14 +4,14 @@ var shop = use('shop')
 
 var alias = args.length > 0 ? args[0] : null
 
-log.console("Checking for updates...")
-shop.update_all(alias)
-
 var packages = shop.list_packages()
 
-log.console(packages)
+log.console("Checking for updates...")
 
-for (var pack of packages)
+for (var pack of packages) {
+  log.console("Updating " + pack)
+  shop.update(pack)
   shop.build_package(pack)
+}
 
 $_.stop()
\ No newline at end of file
diff --git a/source/blob.h b/source/blob.h
index 964e5e32..4fa72936 100644
--- a/source/blob.h
+++ b/source/blob.h
@@ -221,7 +221,6 @@ static int blob_copy_bits(blob *dest, const void *src, size_t from, size_t to) {
 blob *blob_new(size_t capacity) {
   if (capacity < 0) capacity = 0;
   blob *b = calloc(1, sizeof(blob));
-  printf("allocating blob %p size %zu\n", b, capacity);
   if (!b) return NULL;
   if (blob_ensure_capacity(b, capacity) < 0) {
     free(b);
@@ -264,7 +263,6 @@ blob *blob_new_with_fill(size_t length_bits, int logical_value) {
 
 void blob_destroy(blob *b) {
   if (!b) return;
-  printf("destroying blob %p, data %p, length %zu, capacity %zu\n", b, b->data, b->length, b->capacity);
   if (b->data) {
     free(b->data);
     b->data = NULL;
diff --git a/source/cell.h b/source/cell.h
index d4122148..97218234 100644
--- a/source/cell.h
+++ b/source/cell.h
@@ -102,7 +102,8 @@ JSValue js_##ID##_get_##ENTRY (JSContext *js, JSValue self) { \
 #define QJSCLASS(TYPE, ...)\
 JSClassID js_##TYPE##_id;\
 static void js_##TYPE##_finalizer(JSRuntime *rt, JSValue val){\
-TYPE *n = JS_GetOpaque(val, js_##TYPE##_id);\
+JSContext *js = JS_GetContext(rt);\
+TYPE *n = JS_GetOpaque2(js, val, js_##TYPE##_id); \
 TYPE##_free(rt,n);}\
 static JSClassDef js_##TYPE##_class = {\
   .class_name = #TYPE,\
diff --git a/source/qjs_blob.c b/source/qjs_blob.c
index f8535527..8d5d5aa8 100644
--- a/source/qjs_blob.c
+++ b/source/qjs_blob.c
@@ -10,10 +10,7 @@
 // Free function for blob
 void blob_free(JSRuntime *rt, blob *b)
 {
-  if (b) {
-    printf("destroying blob %p blob data %p, length %zu\n", b, b->data, b->length);
-    blob_destroy(b);
-  }
+//  blob_destroy(b);
 }
 
 // Use QJSCLASS macro to generate class boilerplate
@@ -122,15 +119,7 @@ static JSValue js_blob_constructor(JSContext *ctx, JSValueConst new_target,
     return JS_ThrowOutOfMemory(ctx);
   }
 
-  JSValue ret = blob2js(ctx, bd);
-  printf("created blob %p blob data %p, length %zu\n", bd, bd->data, bd->length);
-  // Ensure the returned object's prototype is set correctly for instanceof
-  JSValue ctor_proto = JS_GetPropertyStr(ctx, new_target, "prototype");
-  if (!JS_IsException(ctor_proto)) {
-    JS_SetPrototype(ctx, ret, ctor_proto);
-  }
-  JS_FreeValue(ctx, ctor_proto);
-  return ret;
+  return blob2js(ctx, bd);
 }
 
 // blob.write_bit(logical)
@@ -323,8 +312,6 @@ static JSValue js_blob_read_blob(JSContext *ctx, JSValueConst this_val,
     return JS_ThrowOutOfMemory(ctx);
   }
 
-  printf("stoned copy blob %p blob data %p, length %" PRId64 "\n", new_bd, new_bd->data, new_bd->length);
-  
   return blob2js(ctx, new_bd);
 }
 
@@ -518,7 +505,6 @@ JSValue js_blob_use(JSContext *js) {
   // Explicitly set the prototype property to ensure instanceof works
   JS_SetPropertyStr(js, ctor, "__prototype__", JS_DupValue(js, proto));
   JS_FreeValue(js, proto);
-
   return ctor;
 }
 
@@ -529,8 +515,6 @@ JSValue js_new_blob_stoned_copy(JSContext *js, void *data, size_t bytes)
   b->length = bytes * 8;  // Set the actual length in bits
   blob_make_stone(b);
 
-  printf("stoned copy blob %p blob data %p, length %" PRId64 "\n", b, b->data, b->length);
-  
   return blob2js(js, b);
 }
 
@@ -546,8 +530,14 @@ void *js_get_blob_data(JSContext *js, size_t *size, JSValue v)
     JS_ThrowReferenceError(js, "attempted to read data from a non-stone blob");
     return -1;
   }
-    
+
+  if (b->length % 8 != 0) {
+    JS_ThrowReferenceError(js, "attempted to read data from a non-byte aligned blob");
+    return -1;
+  }
+
   *size = (b->length + 7) / 8;  // Return actual byte size based on bit length
+
   return b->data;
 }
 
@@ -556,13 +546,28 @@ void *js_get_blob_data_bits(JSContext *js, size_t *bits, JSValue v)
   blob *b = js2blob(js, v);
   if (!b) {
     JS_ThrowReferenceError(js, "get_blob_data_bits: not called on a blob");
-    return NULL;
+    return -1;
   }
   if (!b->is_stone) {
     JS_ThrowReferenceError(js, "attempted to read data from a non-stone blob");
-    return NULL;
+    return -1;
   }
     
+  if (!b->data) {
+    JS_ThrowReferenceError(js, "attempted to read data from an empty blob");
+    return -1;
+  }
+
+  if (b->length % 8 != 0) {
+    JS_ThrowReferenceError(js, "attempted to read data from a non-byte aligned blob");
+    return -1;
+  }
+
+  if (b->length == 0) {
+    JS_ThrowReferenceError(js, "attempted to read data from an empty blob");
+    return -1;
+  }
+
   *bits = b->length;
   return b->data;
 }
diff --git a/source/quickjs.c b/source/quickjs.c
index 9b4eae14..f061afdf 100644
--- a/source/quickjs.c
+++ b/source/quickjs.c
@@ -240,6 +240,7 @@ struct JSRuntime {
     int shape_hash_count; /* number of hashed shapes */
     JSShape **shape_hash;
     void *user_opaque;
+    JSContext *js;
 };
 
 struct JSClass {
@@ -1576,6 +1577,7 @@ void JS_FreeRuntime(JSRuntime *rt)
 
 JSContext *JS_NewContextRaw(JSRuntime *rt)
 {
+    assert(!rt->js);
     JSContext *ctx;
     int i;
 
@@ -1599,6 +1601,7 @@ JSContext *JS_NewContextRaw(JSRuntime *rt)
     ctx->regexp_ctor = JS_NULL;
 
     JS_AddIntrinsicBasicObjects(ctx);
+    rt->js = ctx;
     return ctx;
 }
 
@@ -37481,3 +37484,11 @@ JSValue js_debugger_closure_variables(JSContext *ctx, JSValue fn) {
 done:
     return ret;
 }
+
+void *js_debugger_val_address(JSContext *ctx, JSValue val) {
+    return JS_VALUE_GET_PTR(val);
+}
+
+JSContext *JS_GetContext(JSRuntime *rt) {
+    return rt->js;
+}
\ No newline at end of file
diff --git a/source/quickjs.h b/source/quickjs.h
index 6bba1f31..e080fea1 100644
--- a/source/quickjs.h
+++ b/source/quickjs.h
@@ -362,6 +362,7 @@ JS_BOOL JS_IsLiveObject(JSRuntime *rt, JSValueConst obj);
 JSContext *JS_NewContext(JSRuntime *rt);
 void JS_FreeContext(JSContext *s);
 JSContext *JS_DupContext(JSContext *ctx);
+JSContext *JS_GetContext(JSRuntime *rt);
 void *JS_GetContextOpaque(JSContext *ctx);
 void JS_SetContextOpaque(JSContext *ctx, void *opaque);
 JSRuntime *JS_GetRuntime(JSContext *ctx);
@@ -990,6 +991,7 @@ JSValue js_debugger_local_variables(JSContext *ctx, int stack_index);
 JSValue js_debugger_build_backtrace(JSContext *ctx, const uint8_t *cur_pc);
 JSValue js_debugger_fn_info(JSContext *ctx, JSValue fn);
 JSValue js_debugger_fn_bytecode(JSContext *js, JSValue fn);
+void *js_debugger_val_address(JSContext *js, JSValue val);
 
 #undef js_unlikely
 #undef js_force_inline