diff --git a/man/systemd-sysext.xml b/man/systemd-sysext.xml
index f4dd150a53..aa0d42d83c 100644
--- a/man/systemd-sysext.xml
+++ b/man/systemd-sysext.xml
@@ -26,6 +26,7 @@
     <cmdsynopsis>
       <command>systemd-sysext</command>
       <arg choice="opt" rep="repeat">OPTIONS</arg>
+      <arg choice="plain">COMMAND</arg>
     </cmdsynopsis>
 
     <para><literallayout><filename>systemd-sysext.service</filename></literallayout></para>
diff --git a/src/sysext/sysext.c b/src/sysext/sysext.c
index b81f1ebe73..a8593cec4d 100644
--- a/src/sysext/sysext.c
+++ b/src/sysext/sysext.c
@@ -886,7 +886,7 @@ static int verb_help(int argc, char **argv, void *userdata) {
         if (r < 0)
                 return log_oom();
 
-        printf("%1$s [OPTIONS...] [DEVICE]\n"
+        printf("%1$s [OPTIONS...] COMMAND\n"
                "\n%5$sMerge extension images into /usr/ and /opt/ hierarchies.%6$s\n"
                "\n%3$sCommands:%4$s\n"
                "  status                  Show current merge status (default)\n"