diff --git a/MozillaFirefox.changes b/MozillaFirefox.changes
index abbf841..823ddfb 100644
--- a/MozillaFirefox.changes
+++ b/MozillaFirefox.changes
@@ -66,7 +66,7 @@ Sun Nov 15 12:16:53 UTC 2020 - Wolfgang Rosenauer <wr@rosenauer.org>
   NSS >= 3.58
   nodejs >= 10.22.1
 - removed obsolete mozilla-ppc-altivec_static_inline.patch
-- switch to build with clang (as gcc produces only ICEs on TW)
+- disable LTO on TW because of ICEs in gcc
 
 -------------------------------------------------------------------
 Mon Nov  9 10:15:52 UTC 2020 - Wolfgang Rosenauer <wr@rosenauer.org>
diff --git a/MozillaFirefox.spec b/MozillaFirefox.spec
index bdae17f..e1e4d0d 100644
--- a/MozillaFirefox.spec
+++ b/MozillaFirefox.spec
@@ -41,7 +41,7 @@
 %define do_profiling   0
 
 # upstream default is clang (to use gcc for large parts set to 0)
-%define clang_build 1
+%define clang_build 0
 
 # PIE, full relro
 %define build_hardened 1
@@ -508,7 +508,8 @@ ac_add_options --enable-optimize="-O1"
 %endif
 %ifarch x86_64
 # LTO needs newer toolchain stack only (at least GCC 8.2.1 (r268506)
-%if 0%{?suse_version} > 1500
+# TW's gcc is currently also broken with LTO https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93951
+%if 0%{?suse_version} > 1500 && 0%{?suse_version} < 1550
 ac_add_options --enable-lto
 %if 0%{?do_profiling}
 ac_add_options MOZ_PGO=1