diff --git a/sdk_container/src/third_party/portage-stable/eclass/udev.eclass b/sdk_container/src/third_party/portage-stable/eclass/udev.eclass
index 073e5d8acb..8fa73fe13e 100644
--- a/sdk_container/src/third_party/portage-stable/eclass/udev.eclass
+++ b/sdk_container/src/third_party/portage-stable/eclass/udev.eclass
@@ -1,10 +1,15 @@
 # Copyright 1999-2021 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
+
+# Flatcar: this file is modified to still support old EAPIs and to
+# still provide the deprecated systemd_dotmpfilesd functions.
+
+
 # @ECLASS: udev.eclass
 # @MAINTAINER:
 # systemd@gentoo.org
-# @SUPPORTED_EAPIS: 5 6 7 8
+# @SUPPORTED_EAPIS: 0 1 2 3 4 5 6 7
 # @BLURB: Default eclass for determining udev directories.
 # @DESCRIPTION:
 # Default eclass for determining udev directories.
@@ -28,17 +33,18 @@
 # }
 # @CODE
 
-case ${EAPI} in
-	5|6|7|8) ;;
-	*) die "${ECLASS}: EAPI ${EAPI:-0} not supported" ;;
-esac
-
 if [[ -z ${_UDEV_ECLASS} ]]; then
 _UDEV_ECLASS=1
 
 inherit toolchain-funcs
 
-if [[ ${EAPI} == [56] ]]; then
+case ${EAPI:-0} in
+	0|1|2|3|4|5|6|7) ;;
+	*) die "${ECLASS}.eclass API in EAPI ${EAPI} not yet established."
+esac
+
+if [[ ${EAPI:-0} == [0123456] ]]; then
+	RDEPEND=""
 	DEPEND="virtual/pkgconfig"
 else
 	BDEPEND="virtual/pkgconfig"
@@ -83,7 +89,8 @@ get_udevdir() {
 # @FUNCTION: udev_dorules
 # @USAGE: <rule> [...]
 # @DESCRIPTION:
-# Install udev rule(s). Uses doins, thus it is fatal.
+# Install udev rule(s). Uses doins, thus it is fatal in EAPI 4
+# and non-fatal in earlier EAPIs.
 udev_dorules() {
 	debug-print-function ${FUNCNAME} "${@}"
 
@@ -97,7 +104,8 @@ udev_dorules() {
 # @FUNCTION: udev_newrules
 # @USAGE: <oldname> <newname>
 # @DESCRIPTION:
-# Install udev rule with a new name. Uses newins, thus it is fatal.
+# Install udev rule with a new name. Uses newins, thus it is fatal
+# in EAPI 4 and non-fatal in earlier EAPIs.
 udev_newrules() {
 	debug-print-function ${FUNCNAME} "${@}"