The only change from 1.04 to 1.04a is a change in iSCSI user's guide, no binary changes. 1.04 and 1.04a are functionally the same. If you have 1.04 already, you don't need to update to 1.04a. 1.04 is build 243 and 1.04a is build 244. For use with Windows Server 2003; Windows 2000 Sp3; Windows 2000 Sp4; and Windows XP Professional SP1. Included are x86 free and checked builds and IA64 free and checked builds.
Download: Download page at Microsoft.com
Download: Direct link to i386 non-checked build