Firmware 3.21 has just gone live, removing the ability to install Linux on the PS3. However, according to the Japanese PlayStation site, it does a couple of other things too, stuff that nobody’s mentioned before. Don’t get too excited, though, it’s not background downloading, cross-game chat or PS2 playback. Yet.

* PlayStation®Store からダウンロードできる一部のPlayStation®規格ソフトウェアにおいて、動作品質を改善しました。
* MP4ビデオファイルの再生に関するセキュリティ脆弱性に対応しました。

So, what’s that all about? Well, firstly it appears that the quality of of PlayStation format software from the Store has been improved, presumably referring to the PS1 functionality (FFIX?). Secondly, it appears that the security of MP4 video playback has been boosted too, removing some vulnerabilities.
Told you it wasn’t that exciting. Wonder if there was some hole in the MP4 playback, though…