Now that I upgraded the firmware, I can confirm it has the same ridiculous misbehavior where simply browsing directly on any page of the web UI gives a "The request is forbidden" message.
You have to go through it's home page to get to the other pages.
They'll claim it's for security, but it's not true since you can overcome by simply spoofing the referrer in cURL or through a Greasemonkey script (both tested), or probably through some Extension that can change the referrer (not tested).
*Sigh*