diff --git a/.firefox.metadata b/.firefox.metadata
index 96b97d2..19f80b6 100644
--- a/.firefox.metadata
+++ b/.firefox.metadata
@@ -1,5 +1,5 @@
 c822547dbc12e2baebdfdfb38b665e23f0c2513a SOURCES/cbindgen-vendor.tar.xz
-736b0b4313f678de624c0124f61a86893385d110 SOURCES/firefox-91.3.0esr.processed-source.tar.xz
-7b821f5b94cba12efc8a2b86dbd8c7321b453568 SOURCES/firefox-langpacks-91.3.0esr-20211101.tar.xz
+322e0ffb8b442f599b0f5dd695e6f83050b3dc82 SOURCES/firefox-91.4.0esr.processed-source.tar.xz
+74a1b8c9a5f4a96f80af2d3fe542495e3af2423a SOURCES/firefox-langpacks-91.4.0esr-20211201.tar.xz
 b5fd1332d8e0d37339ae170c7bebcb63a40b22e0 SOURCES/nspr-4.32.0-1.el8_1.src.rpm
-29da2158892dc108a7a21fd8411fccf0061481b3 SOURCES/nss-3.67.0-6.el8_1.src.rpm
+8fff814901e03c2518ede2f8992d898f5ba61ed9 SOURCES/nss-3.67.0-7.el8_1.src.rpm
diff --git a/.gitignore b/.gitignore
index 1a94cd1..e79811e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,5 @@
 SOURCES/cbindgen-vendor.tar.xz
-SOURCES/firefox-91.3.0esr.processed-source.tar.xz
-SOURCES/firefox-langpacks-91.3.0esr-20211101.tar.xz
+SOURCES/firefox-91.4.0esr.processed-source.tar.xz
+SOURCES/firefox-langpacks-91.4.0esr-20211201.tar.xz
 SOURCES/nspr-4.32.0-1.el8_1.src.rpm
-SOURCES/nss-3.67.0-6.el8_1.src.rpm
+SOURCES/nss-3.67.0-7.el8_1.src.rpm
diff --git a/README.debrand b/README.debrand
deleted file mode 100644
index 01c46d2..0000000
--- a/README.debrand
+++ /dev/null
@@ -1,2 +0,0 @@
-Warning: This package was configured for automatic debranding, but the changes
-failed to apply.
diff --git a/SOURCES/firefox-nss-addon-hack.patch b/SOURCES/firefox-nss-addon-hack.patch
new file mode 100644
index 0000000..0322707
--- /dev/null
+++ b/SOURCES/firefox-nss-addon-hack.patch
@@ -0,0 +1,19 @@
+diff -up firefox-84.0.2/security/certverifier/NSSCertDBTrustDomain.cpp.nss-hack firefox-84.0.2/security/certverifier/NSSCertDBTrustDomain.cpp
+--- firefox-84.0.2/security/certverifier/NSSCertDBTrustDomain.cpp.nss-hack      2021-01-11 12:12:02.585514543 +0100
++++ firefox-84.0.2/security/certverifier/NSSCertDBTrustDomain.cpp       2021-01-11 12:47:50.345984582 +0100
+@@ -1619,6 +1619,15 @@ SECStatus InitializeNSS(const nsACString
+     return srv;
+   }
+
++  /* Sets the NSS_USE_ALG_IN_ANY_SIGNATURE bit.
++   * does not change NSS_USE_ALG_IN_CERT_SIGNATURE,
++   * so policy will still disable use of sha1 in
++   * certificate related signature processing. */
++  srv = NSS_SetAlgorithmPolicy(SEC_OID_SHA1, NSS_USE_ALG_IN_ANY_SIGNATURE, 0);
++  if (srv != SECSuccess) {
++    NS_WARNING("Unable to use SHA1 for Add-ons, expect broken/disabled Add-ons. See https://bugzilla.redhat.com/show_bug.cgi?id=1908018 for details.");
++  }
++
+   if (nssDbConfig == NSSDBConfig::ReadWrite) {
+     UniquePK11SlotInfo slot(PK11_GetInternalKeySlot());
+     if (!slot) {
diff --git a/SPECS/firefox.spec b/SPECS/firefox.spec
index d920825..956d73f 100644
--- a/SPECS/firefox.spec
+++ b/SPECS/firefox.spec
@@ -128,8 +128,8 @@ end}
 
 Summary:        Mozilla Firefox Web browser
 Name:           firefox
-Version:        91.3.0
-Release:        1%{?dist}
+Version:        91.4.0
+Release:        3%{?dist}
 URL:            https://www.mozilla.org/firefox/
 License:        MPLv1.1 or GPLv2+ or LGPLv2+
 %if 0%{?rhel} == 9
@@ -149,7 +149,7 @@ ExcludeArch:    s390 ppc
 # Link to official tarball: https://hg.mozilla.org/releases/mozilla-release/archive/firefox-%%{version}%%{?pre_version}.source.tar.xz
 Source0:        firefox-%{version}%{?pre_version}.processed-source.tar.xz
 %if %{build_langpacks}
-Source1:        firefox-langpacks-%{version}%{?pre_version}-20211101.tar.xz
+Source1:        firefox-langpacks-%{version}%{?pre_version}-20211201.tar.xz
 %endif
 Source2:        cbindgen-vendor.tar.xz
 Source3:        process-official-tarball
@@ -168,7 +168,7 @@ Source26:       distribution.ini
 Source27:       google-api-key
 Source28:       node-stdout-nonblocking-wrapper
 
-Source403:      nss-3.67.0-6.el8_1.src.rpm
+Source403:      nss-3.67.0-7.el8_1.src.rpm
 Source401:      nss-setup-flags-env.inc
 Source402:      nspr-4.32.0-1.el8_1.src.rpm
 
@@ -184,6 +184,7 @@ Patch6:         build-nss-version.patch
 Patch215:        firefox-enable-addons.patch
 Patch219:        rhbz-1173156.patch
 Patch224:        mozilla-1170092.patch
+Patch225:        firefox-nss-addon-hack.patch
 
 # Upstream patches
 
@@ -424,6 +425,7 @@ echo "use_rustts            %{?use_rustts}"
 %patch215 -p1 -b .addons
 %patch219 -p1 -b .rhbz-1173156
 %patch224 -p1 -b .1170092
+%patch225 -p1 -b .firefox-nss-addon-hack
 
 # Patch for big endian platforms only
 %if 0%{?big_endian}
@@ -480,7 +482,7 @@ echo "ac_add_options --disable-optimize" >> .mozconfig
 %else
 %global optimize_flags "-g -O2"
 %ifarch s390x
-%global optimize_flags "-g -O1"
+%global optimize_flags "-g -O2"
 %endif
 %ifarch ppc64le aarch64
 %global optimize_flags "-g -O2"
@@ -1247,8 +1249,14 @@ gtk-update-icon-cache %{_datadir}/icons/hicolor &>/dev/null || :
 #---------------------------------------------------------------------
 
 %changelog
-* Tue Dec 07 2021 CentOS Sources <bugs@centos.org> - 91.3.0-1.el9.centos
-- Apply debranding changes
+* Wed Dec 22 2021 Jan Horak <jhorak@redhat.com> - 91.4.0-3
+- Enable optimalization on s390x
+
+* Mon Dec 13 2021 Jan Horak <jhorak@redhat.com> - 91.4.0-2
+- Added fix for failing addons signatures.
+
+* Wed Dec 01 2021 Eike Rathke <erack@redhat.com> - 91.4.0-1
+- Update to 91.4.0 build1
 
 * Mon Nov 01 2021 Eike Rathke <erack@redhat.com> - 91.3.0-1
 - Update to 91.3.0 build1