Press Release:
Canon has today posted firmware version 1.0.4 for the EOS 20D digital SLR. This firmware fixes the problem of the shutter release not working when a lens is removed or a lens is attached when the camera is in auto power off mode, and improves the reliability when using some CF cards. This update applies to camera with firmware version 1.0.2. The firmware can be loaded via a CompactFlash card.

WARNING: Some people are reporting issues with this firmware update, our advise is to wait for further information from Canon. There are several threads running on our Canon EOS 20D/ 10D/ D60/ D30 forum talking about cameras being 'killed' by this update. We'll update this story as soon as we get confirmation either way.

Release Notes:

EOS 20D Firmware Version 1.0.4 includes the modification for the following issues;

1) Fixes the problem of shutter release not working.
In rare cases, the camera freezes and the shutter stops working if a lens removed or attached while the camera is in auto power off mode. (In other cases, the camera might hang up during continuous shooting.) - This problem has been fixed.

2) Improves reliability when using some CF cards.
Improved reliability of communication with CF cards