diff -up firefox-84.0/toolkit/moz.configure.disable-elfhack firefox-84.0/toolkit/moz.configure
--- firefox-84.0/toolkit/moz.configure.disable-elfhack	2020-12-10 12:37:30.727243266 +0100
+++ firefox-84.0/toolkit/moz.configure	2020-12-10 12:39:42.771967894 +0100
@@ -1280,7 +1280,7 @@ with only_when("--enable-compile-environ
             help="{Enable|Disable} elf hacks",
         )
 
-        set_config("USE_ELF_HACK", depends_if("--enable-elf-hack")(lambda _: True))
+        set_config("USE_ELF_HACK", depends_if("--enable-elf-hack")(lambda _: False))
 
 
 @depends(check_build_environment)