diff -up firefox-91.0.1/python/mozbuild/mozbuild/frontend/context.py.rhel7-nasm firefox-91.0.1/python/mozbuild/mozbuild/frontend/context.py

--- firefox-91.0.1/python/mozbuild/mozbuild/frontend/context.py.rhel7-nasm	2021-08-31 08:02:10.814740774 +0200

+++ firefox-91.0.1/python/mozbuild/mozbuild/frontend/context.py	2021-08-31 08:04:03.967146994 +0200

@@ -420,7 +420,7 @@ class AsmFlags(BaseCompileFlags):

                 if self._context.config.substs.get("OS_ARCH") == "WINNT":

                     debug_flags += ["-F", "cv8"]

                 elif self._context.config.substs.get("OS_ARCH") != "Darwin":

-                    debug_flags += ["-F", "dwarf"]

+                    debug_flags += ["-f", "elf32"]

             elif (

                 self._context.config.substs.get("OS_ARCH") == "WINNT"

                 and self._context.config.substs.get("CPU_ARCH") == "aarch64"