diff --git a/CLOBBER b/CLOBBER
index 1de258b5c684..c21897ba26bd 100644
--- a/CLOBBER
+++ b/CLOBBER
@@ -22,4 +22,4 @@
 # changes to stick? As of bug 928195, this shouldn't be necessary! Please
 # don't change CLOBBER for WebIDL changes any more.
 
-Modified build files in third_party/libwebrtc - Bug 1871981 - Vendor libwebrtc from fd3b346e27
+Modified build files in third_party/libwebrtc - turn off our 'fake' vpx build that only pointed to media/libvpx/libvpx
diff --git a/third_party/libwebrtc/modules/video_coding/webrtc_libvpx_interface_gn/moz.build b/third_party/libwebrtc/modules/video_coding/webrtc_libvpx_interface_gn/moz.build
index c5dabce8b090..81c9b9d4043c 100644
--- a/third_party/libwebrtc/modules/video_coding/webrtc_libvpx_interface_gn/moz.build
+++ b/third_party/libwebrtc/modules/video_coding/webrtc_libvpx_interface_gn/moz.build
@@ -5,6 +5,9 @@
 
   ### This moz.build was AUTOMATICALLY GENERATED from a GN config,  ###
   ### DO NOT edit it by hand.                                       ###
+if not CONFIG["MOZ_SYSTEM_LIBVPX"]:
+    LOCAL_INCLUDES += [ "/media/libvpx/libvpx/" ]
+    CXXFLAGS += CONFIG["MOZ_LIBVPX_CFLAGS"]
 
 COMPILE_FLAGS["OS_INCLUDES"] = []
 AllowCompilerWarnings()
@@ -25,7 +28,6 @@ LOCAL_INCLUDES += [
     "!/ipc/ipdl/_ipdlheaders",
     "!/third_party/libwebrtc/gen",
     "/ipc/chromium/src",
-    "/media/libvpx/libvpx/",
     "/third_party/libwebrtc/",
     "/third_party/libwebrtc/third_party/abseil-cpp/",
     "/tools/profiler/public"
diff --git a/third_party/libwebrtc/modules/video_coding/webrtc_vp8_gn/moz.build b/third_party/libwebrtc/modules/video_coding/webrtc_vp8_gn/moz.build
index 77a6b3870b6f..82a4d24e97a9 100644
--- a/third_party/libwebrtc/modules/video_coding/webrtc_vp8_gn/moz.build
+++ b/third_party/libwebrtc/modules/video_coding/webrtc_vp8_gn/moz.build
@@ -5,6 +5,9 @@
 
   ### This moz.build was AUTOMATICALLY GENERATED from a GN config,  ###
   ### DO NOT edit it by hand.                                       ###
+if not CONFIG["MOZ_SYSTEM_LIBVPX"]:
+    LOCAL_INCLUDES += [ "/media/libvpx/libvpx/" ]
+    CXXFLAGS += CONFIG["MOZ_LIBVPX_CFLAGS"]
 
 COMPILE_FLAGS["OS_INCLUDES"] = []
 AllowCompilerWarnings()
@@ -25,7 +28,6 @@ LOCAL_INCLUDES += [
     "!/ipc/ipdl/_ipdlheaders",
     "!/third_party/libwebrtc/gen",
     "/ipc/chromium/src",
-    "/media/libvpx/libvpx/",
     "/media/libyuv/",
     "/media/libyuv/libyuv/include/",
     "/third_party/libwebrtc/",
diff --git a/third_party/libwebrtc/modules/video_coding/webrtc_vp9_gn/moz.build b/third_party/libwebrtc/modules/video_coding/webrtc_vp9_gn/moz.build
index 4bece7280761..5bb64f341208 100644
--- a/third_party/libwebrtc/modules/video_coding/webrtc_vp9_gn/moz.build
+++ b/third_party/libwebrtc/modules/video_coding/webrtc_vp9_gn/moz.build
@@ -5,6 +5,9 @@
 
   ### This moz.build was AUTOMATICALLY GENERATED from a GN config,  ###
   ### DO NOT edit it by hand.                                       ###
+if not CONFIG["MOZ_SYSTEM_LIBVPX"]:
+    LOCAL_INCLUDES += [ "/media/libvpx/libvpx/" ]
+    CXXFLAGS += CONFIG["MOZ_LIBVPX_CFLAGS"]
 
 COMPILE_FLAGS["OS_INCLUDES"] = []
 AllowCompilerWarnings()
@@ -25,7 +28,6 @@ LOCAL_INCLUDES += [
     "!/ipc/ipdl/_ipdlheaders",
     "!/third_party/libwebrtc/gen",
     "/ipc/chromium/src",
-    "/media/libvpx/libvpx/",
     "/media/libyuv/",
     "/media/libyuv/libyuv/include/",
     "/third_party/libwebrtc/",
diff --git a/third_party/libwebrtc/moz.build b/third_party/libwebrtc/moz.build
index ca399ca5de94..ae994ffc670b 100644
--- a/third_party/libwebrtc/moz.build
+++ b/third_party/libwebrtc/moz.build
@@ -439,7 +439,6 @@ DIRS += [
     "/third_party/libwebrtc/third_party/abseil-cpp/absl/types/span_gn",
     "/third_party/libwebrtc/third_party/abseil-cpp/absl/types/variant_gn",
     "/third_party/libwebrtc/third_party/abseil-cpp/absl/utility/utility_gn",
-    "/third_party/libwebrtc/third_party/libvpx/libvpx_gn",
     "/third_party/libwebrtc/third_party/libyuv/libyuv_gn",
     "/third_party/libwebrtc/third_party/pffft/pffft_gn",
     "/third_party/libwebrtc/third_party/rnnoise/rnn_vad_gn",