diff --git a/pkgs/applications/networking/browsers/firefox/common.nix b/pkgs/applications/networking/browsers/firefox/common.nix
index f0fe6e1551bf..65ed80695bd8 100644
--- a/pkgs/applications/networking/browsers/firefox/common.nix
+++ b/pkgs/applications/networking/browsers/firefox/common.nix
@@ -228,7 +228,6 @@ buildStdenv.mkDerivation ({
     })
   ]
   ++ lib.optional (lib.versionAtLeast version "86") ./env_var_for_system_dir-ff86.patch
-  ++ lib.optional (lib.versionAtLeast version "90" && lib.versionOlder version "95") ./no-buildconfig-ffx90.patch
   ++ lib.optional (lib.versionAtLeast version "96") ./no-buildconfig-ffx96.patch
   ++ extraPatches;
 
@@ -294,9 +293,6 @@ buildStdenv.mkDerivation ({
   '' + lib.optionalString (lib.versionAtLeast version "100.0") ''
     # Use our own python
     export MACH_BUILD_PYTHON_NATIVE_PACKAGE_SOURCE=system
-  '' + lib.optionalString (lib.versionOlder version "100.0") ''
-    # Use our own python
-    export MACH_USE_SYSTEM_PYTHON=1
 
   '' + lib.optionalString (lib.versionAtLeast version "95.0") ''
     # RBox WASM Sandboxing
diff --git a/pkgs/applications/networking/browsers/firefox/no-buildconfig-ffx90.patch b/pkgs/applications/networking/browsers/firefox/no-buildconfig-ffx90.patch
deleted file mode 100644
index c8d2028f30b2..000000000000
--- a/pkgs/applications/networking/browsers/firefox/no-buildconfig-ffx90.patch
+++ /dev/null
@@ -1,22 +0,0 @@
---- a/docshell/base/nsAboutRedirector.cpp
-+++ b/docshell/base/nsAboutRedirector.cpp
-@@ -66,8 +66,6 @@ static const RedirEntry kRedirMap[] = {
-     {"about", "chrome://global/content/aboutAbout.html", 0},
-     {"addons", "chrome://mozapps/content/extensions/aboutaddons.html",
-      nsIAboutModule::ALLOW_SCRIPT},
--    {"buildconfig", "chrome://global/content/buildconfig.html",
--     nsIAboutModule::URI_SAFE_FOR_UNTRUSTED_CONTENT},
-     {"checkerboard", "chrome://global/content/aboutCheckerboard.html",
-      nsIAboutModule::URI_SAFE_FOR_UNTRUSTED_CONTENT |
-          nsIAboutModule::ALLOW_SCRIPT},
---- a/toolkit/content/jar.mn
-+++ b/toolkit/content/jar.mn
-@@ -39,8 +39,6 @@ toolkit.jar:
-    content/global/plugins.html
-    content/global/plugins.css
-    content/global/plugins.js
--*   content/global/buildconfig.html
--   content/global/buildconfig.css
-    content/global/contentAreaUtils.js
-    content/global/datepicker.xhtml
- #ifndef MOZ_FENNEC