diff --git a/default.nix b/default.nix
index 5bf9da886..704f5b433 100644
--- a/default.nix
+++ b/default.nix
@@ -19,6 +19,24 @@ let
   });
 
 in {
+
+  emacsGit = let
+    repoMeta = super.lib.importJSON (./. + "/repos/emacs.json");
+    name = "emacs-git-${version}";
+    version = builtins.substring 0 7 repoMeta.rev;
+  in (super.emacs.override { srcRepo = true; }).overrideAttrs(old: {
+    inherit name version;
+    src = super.fetchFromGitHub {
+      owner = "emacs-mirror";
+      repo = "emacs";
+      inherit (repoMeta) sha256 rev;
+    };
+    patches = [
+      ./patches/tramp-detect-wrapped-gvfsd.patch
+      ./patches/clean-env.patch
+    ];
+  });
+
   emacsPackagesNgFor = emacs:
     (super.emacsPackagesNgFor emacs).overrideScope'(eself: esuper: {
       xelb = mkExDrv eself "xelb" {
@@ -28,4 +46,5 @@ in {
         packageRequires = [ eself.xelb ];
       };
     });
+
 }
diff --git a/patches/.gitkeep b/patches/.gitkeep
new file mode 100644
index 000000000..e69de29bb
diff --git a/patches/clean-env.patch b/patches/clean-env.patch
new file mode 100644
index 000000000..2ffe8b777
--- /dev/null
+++ b/patches/clean-env.patch
@@ -0,0 +1,16 @@
+Dump temacs in an empty environment to prevent -dev paths from ending
+up in the dumped image.
+
+diff --git a/src/Makefile.in b/src/Makefile.in
+index fd05a45df5..13f529c253 100644
+--- a/src/Makefile.in
++++ b/src/Makefile.in
+@@ -570,7 +570,7 @@ emacs$(EXEEXT): temacs$(EXEEXT) \
+                 lisp.mk $(etc)/DOC $(lisp) \
+                 $(lispsource)/international/charprop.el ${charsets}
+ ifeq ($(DUMPING),unexec)
+-	LC_ALL=C $(RUN_TEMACS) -batch $(BUILD_DETAILS) -l loadup --temacs=dump
++	env -i LC_ALL=C $(RUN_TEMACS) -batch $(BUILD_DETAILS) -l loadup --temacs=dump
+   ifneq ($(PAXCTL_dumped),)
+ 	      $(PAXCTL_dumped) emacs$(EXEEXT)
+   endif
diff --git a/patches/tramp-detect-wrapped-gvfsd.patch b/patches/tramp-detect-wrapped-gvfsd.patch
new file mode 100644
index 000000000..5d16194fd
--- /dev/null
+++ b/patches/tramp-detect-wrapped-gvfsd.patch
@@ -0,0 +1,14 @@
+diff --git a/lisp/net/tramp-gvfs.el b/lisp/net/tramp-gvfs.el
+index f370abba31..f2806263a9 100644
+--- a/lisp/net/tramp-gvfs.el
++++ b/lisp/net/tramp-gvfs.el
+@@ -164,7 +164,8 @@ tramp-gvfs-enabled
+     (and (featurep 'dbusbind)
+ 	 (tramp-compat-funcall 'dbus-get-unique-name :system)
+ 	 (tramp-compat-funcall 'dbus-get-unique-name :session)
+-	 (or (tramp-compat-process-running-p "gvfs-fuse-daemon")
++	 (or (tramp-compat-process-running-p ".gvfsd-fuse-wrapped")
++             (tramp-compat-process-running-p "gvfs-fuse-daemon")
+ 	     (tramp-compat-process-running-p "gvfsd-fuse"))))
+   "Non-nil when GVFS is available.")
+ 
diff --git a/repos/emacs.json b/repos/emacs.json
new file mode 100644
index 000000000..0c029b1c6
--- /dev/null
+++ b/repos/emacs.json
@@ -0,0 +1 @@
+{"rev": "a48726ebae2f44ed15b97cb72bc7eca199d8de47", "sha256": "1ldn6cjxhc42dj3rg7balpnq8k5a55karwqy7yld7as6cj2zx703", "version": "20190723.0"}
diff --git a/test.nix b/test.nix
index c8c47b8f9..44950bf59 100644
--- a/test.nix
+++ b/test.nix
@@ -1,6 +1,9 @@
-with import <nixpkgs> {
-  overlays = [ (import ./default.nix) ];
-};
-emacsWithPackages(epkgs: [
+{ pkgs ? import <nixpkgs> { overlays = [ (import ./default.nix) ]; } }:
+
+let
+  package = pkgs.emacsGit;
+  emacsPackages = pkgs.emacsPackagesNgGen package;
+  emacsWithPackages = emacsPackages.emacsWithPackages;
+in emacsWithPackages(epkgs: [
   epkgs.exwm
 ])
diff --git a/update b/update
index 11e1d1a67..65e192213 100755
--- a/update
+++ b/update
@@ -3,21 +3,23 @@
 set -euxo pipefail
 
 function update_repo() {
-    repo=$1
+    owner=$1
+    repo=$2
     echo $repo
 
     # Get relevant data (commit id and timestamp) for the latest commit
-    commit_data=$(curl "https://github.com/ch11ng/$repo/commits/master.atom" | xmlstarlet sel -N atom="http://www.w3.org/2005/Atom" -t -m /atom:feed/atom:entry -v "concat(atom:id,'/',atom:updated)" -n | head -n 1)
+    commit_data=$(curl "https://github.com/$owner/$repo/commits/master.atom" | xmlstarlet sel -N atom="http://www.w3.org/2005/Atom" -t -m /atom:feed/atom:entry -v "concat(atom:id,'/',atom:updated)" -n | head -n 1)
 
     # Extract commit sha and build a version number based on date: YYYYMMDD.0
     commit_sha=$(echo $commit_data | cut -d '/' -f 2)
     version_number=$(echo $commit_data | cut -d '/' -f 3 | cut -d 'T' -f 1 | sed 's/-//g').0
 
-    digest=$(nix-prefetch-url --unpack "https://github.com/ch11ng/$repo/archive/${commit_sha}.tar.gz")
+    digest=$(nix-prefetch-url --unpack "https://github.com/$owner/$repo/archive/${commit_sha}.tar.gz")
     echo "{\"rev\": \"${commit_sha}\", \"sha256\": \"${digest}\", \"version\": \"${version_number}\"}" > repos/$repo.json
 }
 
-update_repo exwm
-update_repo xelb
+update_repo ch11ng exwm
+update_repo ch11ng xelb
+update_repo emacs-mirror emacs
 
 nix-build --no-out-link --show-trace ./test.nix