So the command was accepted? That's actually more interesting than if it didn't respond at all. There are a few additional steps that IRIS could have used to obfuscate the menu with basic settings, such as limiting access to httpS, changing to a non-standard port, or multiple users with limited access. First off, you mention RC8222 but I couldn't find any reference to that model number. Did you mean to say RC8221?

If you feel like pursuing this further, please run the following commands and post the results:

/util/query.cgi?extension=yes

/adm/sysinfo.cgi

/adm/get_group.cgi?group=HTTP

/adm/get_group.cgi?group=USER