diff --git a/src/core/main.c b/src/core/main.c
index 85bf558e90..1d9dec55c3 100644
--- a/src/core/main.c
+++ b/src/core/main.c
@@ -452,16 +452,13 @@ static int parse_proc_cmdline_item(const char *key, const char *value, void *dat
                 if (proc_cmdline_value_missing(key, value))
                         return 0;
 
-                if (env_assignment_is_valid(value)) {
-                        char **env;
-
-                        env = strv_env_set(arg_default_environment, value);
-                        if (!env)
+                if (!env_assignment_is_valid(value))
+                        log_warning("Environment variable assignment '%s' is not valid. Ignoring.", value);
+                else {
+                        r = strv_env_replace_strdup(&arg_default_environment, value);
+                        if (r < 0)
                                 return log_oom();
-
-                        arg_default_environment = env;
-                } else
-                        log_warning("Environment variable name '%s' is not valid. Ignoring.", value);
+                }
 
         } else if (proc_cmdline_key_streq(key, "systemd.machine_id")) {