The Xbox 360 patch for RB2 went live just the other day. Below are the release notes for it.
Rock Band 2 Patch 1 (360)
Update Version 1.3(NA)
Update Version 1.1(EFIGS)
-Adjusted crosstalk values for drum hardware.
-Fix for remote drum fills being silent – users will now hear the drum track when drum fills.
-Fixed overlapping drum fill bug on drum track.
-Fixed rare network crash involving client signing out during setlist creation.
-Fixed rare crash on calibration screen when users mash guitar controller buttons.
-Fixed bug where Leaderboard scores in Band World Tour were not uploading after users played the first song.
-Fixed bug where Leaderboard career scores were posted including DLC songs and not just disc songs as originally intended.
-Fixed rare bug where some combination of local and remote players signed in as guests and gamertags could result in loss of band data if the session owner signed out during a small interval where the game was caching the band data.