diff --git a/MozillaFirefox.changes b/MozillaFirefox.changes
index 5c71efb..68f9c82 100644
--- a/MozillaFirefox.changes
+++ b/MozillaFirefox.changes
@@ -1,3 +1,9 @@
+-------------------------------------------------------------------
+Tue May 23 14:00:40 UTC 2017 - wr@rosenauer.org
+
+- remove -fno-inline-small-functions and explicitely optimize with
+  -O2 for openSUSE > 13.2/Leap 42 to work with gcc7 (boo#1040105)
+
 -------------------------------------------------------------------
 Mon May  8 08:28:17 UTC 2017 - wr@rosenauer.org
 
diff --git a/MozillaFirefox.spec b/MozillaFirefox.spec
index da0406f..3a05e69 100644
--- a/MozillaFirefox.spec
+++ b/MozillaFirefox.spec
@@ -295,9 +295,9 @@ export BUILD_OFFICIAL=1
 export MOZ_TELEMETRY_REPORTING=1
 export MOZ_GOOGLE_API_KEY=%{_google_api_key}
 export CFLAGS="%{optflags} -fno-strict-aliasing"
-# boo#986541: add -fno-delete-null-pointer-checks and -fno-inline-small-functions for gcc6
+# boo#986541: add -fno-delete-null-pointer-checks for gcc6
 %if 0%{?suse_version} > 1320
-export CFLAGS="$CFLAGS -fno-delete-null-pointer-checks -fno-inline-small-functions"
+export CFLAGS="$CFLAGS -fno-delete-null-pointer-checks"
 %endif
 %ifarch %arm
 export CFLAGS="${CFLAGS/-g / }"
@@ -337,6 +337,10 @@ ac_add_options --enable-default-toolkit=cairo-gtk2
 %if 0%{?build_hardened}
 ac_add_options --enable-pie
 %endif
+# gcc7 (boo#104105)
+%if 0%{?suse_version} > 1320
+ac_add_options --enable-optimize="-g -O2"
+%endif
 %ifarch %ix86 %arm
 %if 0%{?suse_version} > 1230
 ac_add_options --disable-optimize