diff --git a/testing/firefox/files/mozconfig b/testing/firefox/files/mozconfig
index 779cf640..6374f62f 100644
--- a/testing/firefox/files/mozconfig
+++ b/testing/firefox/files/mozconfig
@@ -22,7 +22,7 @@ ac_add_options --disable-install-strip
 ac_add_options --disable-strip
 ac_add_options --disable-profiling
 ac_add_options --disable-maintenance-service
-ac_add_options --disable-em
+ac_add_options --disable-eme
 ac_add_options --enable-optimize="$CFLAGS"
 
 ac_add_options --enable-official-branding