diff --git a/third_party/lisp/mime4cl/.skip-subtree b/third_party/lisp/mime4cl/.skip-subtree
new file mode 100644
index 000000000..5051f60d6
--- /dev/null
+++ b/third_party/lisp/mime4cl/.skip-subtree
@@ -0,0 +1 @@
+prevent readTree from creating entries for subdirs that don't contain an .nix files
diff --git a/third_party/lisp/mime4cl/OWNERS b/third_party/lisp/mime4cl/OWNERS
new file mode 100644
index 000000000..f16dd105d
--- /dev/null
+++ b/third_party/lisp/mime4cl/OWNERS
@@ -0,0 +1,3 @@
+inherited: true
+owners:
+  - sterni
diff --git a/third_party/lisp/mime4cl/README b/third_party/lisp/mime4cl/README
new file mode 100644
index 000000000..73f0efbda
--- /dev/null
+++ b/third_party/lisp/mime4cl/README
@@ -0,0 +1,7 @@
+MIME4CL is a Common Lisp library for dealing with MIME messages.
+It has originally been written by Walter C. Pelissero and vendored
+into depot as upstream has become inactive and provides no repo
+of any kind. Upstream and depot version may diverge.
+
+Upstream Website: http://wcp.sdf-eu.org/software/#mime4cl
+Vendored Tarball: http://wcp.sdf-eu.org/software/mime4cl-20150207T211851.tbz
diff --git a/third_party/lisp/mime4cl/default.nix b/third_party/lisp/mime4cl/default.nix
new file mode 100644
index 000000000..516577407
--- /dev/null
+++ b/third_party/lisp/mime4cl/default.nix
@@ -0,0 +1,48 @@
+# Copyright (C) 2021 by the TVL Authors
+# SPDX-License-Identifier: LGPL-2.1-or-later
+{ depot, pkgs, ... }:
+
+depot.nix.buildLisp.library {
+  name = "mime4cl";
+
+  deps = [
+    depot.third_party.lisp.sclf
+    depot.third_party.lisp.npg
+  ];
+
+  srcs = [
+    ./package.lisp
+    ./endec.lisp
+    ./streams.lisp
+    ./mime.lisp
+    ./address.lisp
+  ];
+
+  tests = {
+    name = "mime4cl-tests";
+
+    srcs = [
+      ./test/rt.lisp
+      ./test/package.lisp
+      (pkgs.writeText "nix-samples.lisp" ''
+        (in-package :mime4cl-tests)
+
+        ;; missing from the tarball completely
+        (defvar *samples-directory* (pathname "/this/does/not/exist"))
+        ;; override auto discovery which doesn't work in store
+        (defvar *sample1-file* (pathname "${./test/sample1.msg}"))
+      '')
+      ./test/endec.lisp
+      ./test/address.lisp
+      ./test/mime.lisp
+    ];
+
+    expression = "(rtest:do-tests)";
+  };
+
+  # limited by sclf
+  brokenOn = [
+    "ccl"
+    "ecl"
+  ];
+}
diff --git a/third_party/lisp/mime4cl/streams.lisp b/third_party/lisp/mime4cl/streams.lisp
index 4b3da19a9..64c7adeec 100644
--- a/third_party/lisp/mime4cl/streams.lisp
+++ b/third_party/lisp/mime4cl/streams.lisp
@@ -1,6 +1,7 @@
  ;;; eds.lisp --- En/De-coding Streams
 
  ;;; Copyright (C) 2012 by Walter C. Pelissero
+ ;;; Copyright (C) 2021 by the TVL Authors
 
  ;;; Author: Walter C. Pelissero <walter@pelissero.de>
  ;;; Project: mime4cl
@@ -63,7 +64,8 @@
 	       :initarg :dont-close)))
 
 (defmethod stream-file-position ((stream coder-stream-mixin) &optional position)
-  (file-position (slot-value stream 'real-stream) position))
+  (apply #'file-position (remove nil (list (slot-value stream 'real-stream)
+                                           position))))
 
 (defclass coder-input-stream-mixin (fundamental-binary-input-stream coder-stream-mixin)
   ())
diff --git a/third_party/lisp/mime4cl/test/mime.lisp b/third_party/lisp/mime4cl/test/mime.lisp
index d1a56b0c0..1488f927f 100644
--- a/third_party/lisp/mime4cl/test/mime.lisp
+++ b/third_party/lisp/mime4cl/test/mime.lisp
@@ -1,6 +1,7 @@
  ;;; mime.lisp --- MIME regression tests
 
  ;;; Copyright (C) 2012 by Walter C. Pelissero
+ ;;; Copyright (C) 2021 by the TVL Authors
 
  ;;; Author: Walter C. Pelissero <walter@pelissero.de>
  ;;; Project: mime4cl
@@ -28,11 +29,13 @@
 			 *load-pathname*
 			 #P"")))
 
+(defvar *sample1-file* (make-pathname :defaults #.(or *compile-file-pathname*
+                                                      *load-pathname*)
+                                      :name "sample1"
+                                      :type "msg"))
+
 (deftest mime.1
-    (let* ((orig (mime-message (make-pathname :defaults #.(or *compile-file-pathname*
-							   *load-pathname*)
-					   :name "sample1"
-					   :type "msg")))
+    (let* ((orig (mime-message *sample1-file*))
 	   (dup (mime-message (with-output-to-string (out) (encode-mime-part orig out)))))
       (mime= orig dup))
   t)