diff --git a/extra/firefox/build b/extra/firefox/build
index 3e279a7b..e41f136f 100755
--- a/extra/firefox/build
+++ b/extra/firefox/build
@@ -34,6 +34,24 @@ rm -rf "$1/usr/lib/firefox-devel"
 rm -rf "$1/usr/share/idl"
 rm -rf "$1/usr/lib/firefox/gtk2"
 
-# Install Ghack's user.js.
+# Disable nasty features by default.
+# This extends the Ghacks user.js file.
+cat >> user.js <<EOF
+// Disable DNS over HTTPS.
+user_pref("network.trr.mode", 5);
+
+// Disable location aware browsing.
+user_pref("geo.enabled", false);
+
+// Disable auto extension updates/installs.
+user_pref("extensions.update.enabled", false);
+user_pref("extensions.update.autoUpdateDefault", false);
+
+// Disable Screenshots extension.
+user_pref("extensions.screenshots.disabled", true);
+user_pref("extensions.screenshots.upload-disabled", true);
+EOF
+
+# Install Ghacks user.js.
 mkdir -p "$1/usr/lib/firefox/browser/defaults/preferences/"
 cp -f ./user.js "$1/usr/lib/firefox/browser/defaults/preferences/vendor.js"
diff --git a/extra/firefox/sources b/extra/firefox/sources
index cf70694d..f1b1e4a5 100644
--- a/extra/firefox/sources
+++ b/extra/firefox/sources
@@ -1,6 +1,6 @@
 https://archive.mozilla.org/pub/firefox/releases/69.0/source/firefox-69.0.source.tar.xz firefox/
 https://ftp.gnu.org/gnu/autoconf/autoconf-2.13.tar.gz autoconf2.13/
-https://raw.githubusercontent.com/ghacksuserjs/ghacks-user.js/6618bf5f7693a15c77f863b6c5d9dabd5f72972a/user.js firefox/
+https://raw.githubusercontent.com/ghacksuserjs/ghacks-user.js/335299a0cfc083e86e1b88e849999b5daffd5a58/user.js firefox/
 files/mozconfig firefox/
 files/stab.h firefox/toolkit/crashreporter/google-breakpad/src/
 patches/fix-fortify-system-wrappers.patch firefox/