Canon has announced a Firmware update for the EOS 550D camera.

Firmware version 1.0.9 incorporates the following fixes.

1.Fixes a phenomenon in which tone jumps become noticeable in some images, depending on the shooting scene, when shooting with the Auto Lighting Optimizer settings (Low / Standard / Strong).

The firmware can be downloaded from here: http://web.canon.jp/imaging/eosd/fir.../firmware.html