Super Mario 3D Land isn't due until November 13 in the States, but Japanese gamers are cracking open their copies to find a surprise. The game includes a mandatory firmware update for the 3DS, which adds a new feature for your friends list.
Tiny Cartridge reports that the update adds a button next to friends that lets you jump into their game in progress, presuming of course that you have the same game that supports online multiplayer. The update also brings Nintendo's latest in its never-ending piracy fight, blocking flashcarts.
Since the update is mandatory, it seems likely that Nintendo will push it out to all users through standard means as well. Another firmware update is also planned for later in the month, which will add 3D video recording, new StreetPass challenges, 3DS-to-3DS software transfers, and new eShop tweaks.