diff --git a/prelude/bootstrap.js b/prelude/bootstrap.js
index 2f85f902..93ab1e79 100644
--- a/prelude/bootstrap.js
+++ b/prelude/bootstrap.js
@@ -1722,12 +1722,16 @@ function payloadFileSync(pointer) {
     fs.promises.stat = util.promisify(fs.stat);
     fs.promises.lstat = util.promisify(fs.lstat);
 
-    /*
     fs.promises.read = util.promisify(fs.read);
     fs.promises.realpath = util.promisify(fs.realpath);
     fs.promises.fstat = util.promisify(fs.fstat);
+    fs.promises.statfs = util.promisify(fs.fstat);
     fs.promises.access = util.promisify(fs.access);
-  */
+
+    // TODO: all promises methods that try to edit files in snapshot should throw
+    // TODO implement missing methods
+    // fs.promises.readlink ?
+    // fs.promises.opendir ?
   }
 
   // ///////////////////////////////////////////////////////////////
diff --git a/prelude/diagnostic.js b/prelude/diagnostic.js
index 64acac20..22201a58 100644
--- a/prelude/diagnostic.js
+++ b/prelude/diagnostic.js
@@ -80,7 +80,7 @@ function humanSize(bytes) {
     return totalSize;
   }
   function wrap(obj, name) {
-    const f = fs[name];
+    const f = obj[name];
     obj[name] = (...args) => {
       const args1 = Object.values(args);
       console.log(
@@ -111,6 +111,7 @@ function humanSize(bytes) {
       wrap(fs, 'open');
       wrap(fs, 'readSync');
       wrap(fs, 'read');
+      wrap(fs, 'readFile');
       wrap(fs, 'writeSync');
       wrap(fs, 'write');
       wrap(fs, 'closeSync');
@@ -131,6 +132,18 @@ function humanSize(bytes) {
       wrap(fs, 'exists');
       wrap(fs, 'accessSync');
       wrap(fs, 'access');
+
+      wrap(fs.promises, 'open');
+      wrap(fs.promises, 'read');
+      wrap(fs.promises, 'readFile');
+      wrap(fs.promises, 'write');
+      wrap(fs.promises, 'readdir');
+      wrap(fs.promises, 'realpath');
+      wrap(fs.promises, 'stat');
+      wrap(fs.promises, 'lstat');
+      wrap(fs.promises, 'fstat');
+      wrap(fs.promises, 'access');
+      wrap(fs.promises, 'copyFile');
     }
   }
 })();