diff --git a/firefox.spec b/firefox.spec
index dc01d45..b5f491e 100644
--- a/firefox.spec
+++ b/firefox.spec
@@ -61,7 +61,9 @@ ExcludeArch: ppc64le
 %global system_libvpx     0
 %global system_jpeg       1
 %global system_pixman     1
-%global use_bundled_cbindgen  1
+# Bundled cbindgen makes build slow.
+# Enable only if system cbindgen is not available.
+%global use_bundled_cbindgen  0
 %if %{debug_build}
 %global release_build     0
 %endif
@@ -234,7 +236,6 @@ Patch407:        mozilla-1667096.patch
 
 # PGO/LTO patches
 Patch600:        pgo.patch
-Patch602:        mozilla-1516803.patch
 Patch603:        firefox-gcc-always-inline.patch
 
 # tentative patch for RUSTFLAGS parsing issue:
@@ -508,7 +509,6 @@ This package contains results of tests executed during build.
 %if %{build_with_pgo}
 %if !%{build_with_clang}
 %patch600 -p1 -b .pgo
-%patch602 -p1 -b .1516803
 %endif
 %endif
 %patch603 -p1 -b .inline
@@ -625,7 +625,8 @@ chmod a-x third_party/rust/ash/src/extensions/nv/*.rs
 
 %build
 # Disable LTO to work around rhbz#1883904
-%define _lto_cflags %{nil}
+# Is that already fixed?
+# %define _lto_cflags %{nil}
 
 %if 0%{?use_bundled_cbindgen}
 mkdir -p my_rust_vendor
@@ -643,6 +644,8 @@ EOL
 env CARGO_HOME=.cargo cargo install cbindgen
 export PATH=`pwd`/.cargo/bin:$PATH
 cd -
+%else
+export CBINDGEN=/usr/bin/cbindgen
 %endif
 
 mkdir %{_buildrootdir}/bin || :
@@ -707,9 +710,13 @@ echo "export NM=\"gcc-nm\"" >> .mozconfig
 echo "export RANLIB=\"gcc-ranlib\"" >> .mozconfig
 %endif
 %if 0%{?build_with_pgo}
-echo "ac_add_options MOZ_PGO=1" >> .mozconfig
 # PGO build doesn't work with ccache
 export CCACHE_DISABLE=1
+export GCOV_PREFIX=`pwd -P`/objdir
+export GCOV_PREFIX_STRIP=$(( $(echo `pwd -P`|tr -c -d '/' |wc -c )+2 ))
+env | grep GCOV
+echo "ac_add_options --enable-lto" >> .mozconfig
+echo "ac_add_options MOZ_PGO=1" >> .mozconfig
 %endif
 
 # Require 2 GB of RAM per CPU core
diff --git a/mozilla-1516803.patch b/mozilla-1516803.patch
deleted file mode 100644
index 30d1fdf..0000000
--- a/mozilla-1516803.patch
+++ /dev/null
@@ -1,15 +0,0 @@
-diff -up firefox-84.0/security/sandbox/linux/moz.build.1516803 firefox-84.0/security/sandbox/linux/moz.build
---- firefox-84.0/security/sandbox/linux/moz.build.1516803      2020-12-10 16:17:55.425139545 +0100
-+++ firefox-84.0/security/sandbox/linux/moz.build      2020-12-10 16:29:21.945860841 +0100
-@@ -114,9 +114,8 @@ if CONFIG["CC_TYPE"] in ("clang", "gcc")
- # gcc lto likes to put the top level asm in syscall.cc in a different partition
- # from the function using it which breaks the build.  Work around that by
- # forcing there to be only one partition.
--for f in CONFIG["OS_CXXFLAGS"]:
--    if f.startswith("-flto") and CONFIG["CC_TYPE"] != "clang":
--        LDFLAGS += ["--param lto-partitions=1"]
-+if CONFIG['CC_TYPE'] != 'clang':
-+    LDFLAGS += ['--param', 'lto-partitions=1']
- 
- DEFINES["NS_NO_XPCOM"] = True
- DisableStlWrapping()
diff --git a/pgo.patch b/pgo.patch
index ac3694e..cae0648 100644
--- a/pgo.patch
+++ b/pgo.patch
@@ -59,17 +59,6 @@ diff -up firefox-112.0/build/pgo/profileserver.py.pgo firefox-112.0/build/pgo/pr
  
      with TemporaryDirectory() as profilePath:
          # TODO: refactor this into mozprofile
-@@ -213,6 +226,10 @@ if __name__ == "__main__":
-             print("Firefox exited successfully, but produced a crashreport")
-             sys.exit(1)
- 
-+        print('Copying profile data....')
-+        os.system('pwd');
-+        os.system('tar cf profdata.tar.gz `find . -name "*.gcda"`; cd ..; tar xf instrumented/profdata.tar.gz;');
-+
-         llvm_profdata = env.get("LLVM_PROFDATA")
-         if llvm_profdata:
-             profraw_files = glob.glob("*.profraw")
 diff -up firefox-112.0/build/unix/mozconfig.unix.pgo firefox-112.0/build/unix/mozconfig.unix
 --- firefox-112.0/build/unix/mozconfig.unix.pgo	2023-04-06 21:27:32.537089073 +0200
 +++ firefox-112.0/build/unix/mozconfig.unix	2023-04-06 21:28:54.987949124 +0200