There may be a working version here:
http://chdk.setepontos.com/index.php/topic,2468.msg36383.html#msg36383achurch:
Apologies for jumping in on the topic, but in case it's of any use, I've slightly modified the 1.02b source code and obtained a build that seems to work with 1.03a. Source diff (against SVN r782, with the platform/sx10/sub/102b directory copied to 103a) and DISKBOOT.BIN here.
It doesn't have the PS.FI2 built so it's not instantly bootable, but give it a day or two for someone to get this built and testing can start.
