diff --git a/Makefile b/Makefile
index 090fca3..c112679 100644
--- a/Makefile
+++ b/Makefile
@@ -27,13 +27,11 @@ install: all
 		"$(DESTDIR)/etc/firefox/policies/policies.json"
 	install -Dm644 src/prefs.js \
 		"$(DESTDIR)/$(FIREFOX_DIR)/defaults/pref/mobile-config.js"
+	install -Dm644 src/mobile-config-autoconfig.js \
+		"$(DESTDIR)/$(FIREFOX_DIR)/mobile-config-autoconfig.js"
 	install -Dm644 "out/home.html" \
 		"$(DESTDIR)/usr/share/mobile-config-firefox/home.html"
 	install -Dm644 "out/userChrome.css" \
 		"$(DESTDIR)/etc/mobile-config-firefox/userChrome.css"
-	install -Dm755 "src/mobile-config-firefox.sh" \
-		"$(DESTDIR)/usr/mobile-config/bin/firefox"
-	install -Dm755 "src/mobile-config-path.sh" \
-		"$(DESTDIR)/etc/profile.d/mobile-config-path.sh"
 
 .PHONY: all clean install
diff --git a/src/mobile-config-autoconfig.js b/src/mobile-config-autoconfig.js
new file mode 100644
index 0000000..07e3194
--- /dev/null
+++ b/src/mobile-config-autoconfig.js
@@ -0,0 +1,33 @@
+// Copyright 2020 Arnaud Ferraris, Oliver Smith
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+// This is a Firefox autoconfig file:
+// https://support.mozilla.org/en-US/kb/customizing-firefox-using-autoconfig
+
+// Import custom userChrome.css on startup or new profile creation
+const {classes: Cc, interfaces: Ci, utils: Cu} = Components;
+Cu.import("resource://gre/modules/Services.jsm");
+Cu.import("resource://gre/modules/FileUtils.jsm");
+
+// Create <profile>/chrome/ directory if not already present
+var chromeDir = Services.dirsvc.get("ProfD", Ci.nsIFile);
+chromeDir.append("chrome");
+if (!chromeDir.exists()) {
+  chromeDir.create(Ci.nsIFile.DIRECTORY_TYPE, FileUtils.PERMS_DIRECTORY);
+}
+
+// Create nsIFile objects for userChrome.css in <profile>/chrome/ and in /etc/
+var chromeFile = chromeDir.clone();
+chromeFile.append("userChrome.css");
+var defaultChrome = new FileUtils.File("/etc/mobile-config-firefox/userChrome.css");
+
+// Remove the existing userChrome.css if older than the installed one
+if (chromeFile.exists() && defaultChrome.exists() &&
+    chromeFile.lastModifiedTime < defaultChrome.lastModifiedTime) {
+  chromeFile.remove(false);
+}
+
+// Copy userChrome.css to <profile>/chrome/
+if (!chromeFile.exists()) {
+  defaultChrome.copyTo(chromeDir, "userChrome.css");
+}
diff --git a/src/mobile-config-firefox.sh b/src/mobile-config-firefox.sh
deleted file mode 100644
index 842395c..0000000
--- a/src/mobile-config-firefox.sh
+++ /dev/null
@@ -1,39 +0,0 @@
-#!/bin/sh
-# Copyright 2020 Oliver Smith
-# SPDX-License-Identifier: GPL-3.0-or-later
-
-# Create chrome/userChrome.css symlink in a firefox profile dir
-# $1: path to profile dir, e.g. "/home/user/.mozilla/firefox/asdf.default"
-prepare_profile() {
-	mkdir -p "$1/chrome"
-	if ! [ -e "$1/chrome/userChrome.css" ]; then
-		ln -sv /etc/mobile-config-firefox/userChrome.css \
-			"$1/chrome/userChrome.css"
-	fi
-}
-
-if [ -e ~/.mozilla/firefox/profiles.ini ]; then
-	# Firefox was started without this wrapper and created profiles.ini.
-	# Add the userChrome.css symlink to all existing profiles, then let
-	# firefox run with the default profile.
-
-	for profiledir in ~/.mozilla/firefox/*/; do
-		if ! [ -e "$profiledir/prefs.js" ]; then
-			continue
-		fi
-
-		prepare_profile "$profiledir"
-	done
-
-	exec /usr/bin/firefox "$@"
-else
-	# Firefox was not started without this wrapper. Create a profile dir
-	# called "firefox.default" if it does not exist yet, and add the
-	# userChrome.css symlink. Let firefox use this profile. It will not
-	# create the profiles.ini file.
-
-	profiledir=~/.mozilla/firefox/firefox.default
-	prepare_profile "$profiledir"
-
-	exec /usr/bin/firefox --profile "$profiledir" "$@"
-fi
diff --git a/src/mobile-config-path.sh b/src/mobile-config-path.sh
deleted file mode 100644
index d33dbb6..0000000
--- a/src/mobile-config-path.sh
+++ /dev/null
@@ -1,3 +0,0 @@
-#!/bin/sh
-
-export PATH="/usr/local/bin:/usr/mobile-config/bin:$PATH"
diff --git a/src/prefs.js b/src/prefs.js
index b8e9b79..12113cf 100644
--- a/src/prefs.js
+++ b/src/prefs.js
@@ -1,6 +1,10 @@
 // Copyright 2020 Oliver Smith, Martijn Braam
 // SPDX-License-Identifier: GPL-3.0-or-later
 
+// Set up autoconfig (we use it to copy/update userChrome.css into profile dir)
+pref('general.config.filename', "mobile-config-autoconfig.js");
+pref('general.config.obscure_value', 0);
+
 // Select a mobile user agent for firefox (same as tor browser on android)
 pref('general.useragent.override', 'Mozilla/5.0 (Android 6.0; Mobile; rv:68.0) Gecko/20100101 Firefox/68.0');