diff --git a/combustion b/combustion
index 78450c9..caba864 100644
--- a/combustion
+++ b/combustion
@@ -79,6 +79,15 @@ cleanup() {
 
 	# umount and remount so that the new default subvol is used
 	umount -R /sysroot
+	# Manual umount confuses systemd sometimes because it's async and the
+	# .mount unit might still be active when the "start" is queued, making
+	# it a noop, which ultimately leaves /sysroot unmounted
+	# (https://github.com/systemd/systemd/issues/20329). To avoid that,
+	# wait until systemd processed the umount events. In a chroot (or with
+	# SYSTEMD_OFFLINE=1) systemctl always succeeds, so avoid an infinite loop.
+	if ! systemctl is-active does-not-exist.mount; then
+		while systemctl is-active sysroot.mount; do sleep 0.5; done
+	fi
 	systemctl start sysroot.mount
 }
 
@@ -96,6 +105,9 @@ if ! [ -d "${config_mount}/combustion" ]; then
 	exit 0
 fi
 
+# Make sure /sysroot is mounted
+systemctl start sysroot.mount
+
 # Copy config
 mkdir "${exchangedir}"
 config_dir="${exchangedir}/config"
diff --git a/combustion.changes b/combustion.changes
index d1784f4..ea4957d 100644
--- a/combustion.changes
+++ b/combustion.changes
@@ -1,3 +1,10 @@
+-------------------------------------------------------------------
+Tue Jul 27 06:37:56 UTC 2021 - Fabian Vogt <fvogt@suse.com>
+
+- Drop explicit dependency on sysroot.mount. Instead, handle starting and
+  stopping of the unit explicitly to avoid conflicts.
+- Add workaround for gh#systemd/systemd#20329
+
 -------------------------------------------------------------------
 Mon Jun 21 07:07:23 UTC 2021 - Fabian Vogt <fvogt@suse.com>
 
diff --git a/combustion.service b/combustion.service
index 129c61a..d69426a 100644
--- a/combustion.service
+++ b/combustion.service
@@ -5,8 +5,10 @@ DefaultDependencies=false
 ConditionKernelCommandLine=|ignition.firstboot
 ConditionKernelCommandLine=|combustion.firstboot
 
-Requires=sysroot.mount
-After=sysroot.mount
+# /sysroot needs to be available, but it's temporarily stopped
+# for remounting so a direct requirement is not possible
+Requires=initrd-root-device.target
+After=initrd-root-device.target
 
 # combustion-prepare sets up network, if required
 Requires=combustion-prepare.service