Thanks for the welcome.
I have received my camera (today) and verified that it has Firmware Version 1.01C (according to EXIFTOOL anyway).
I have looked at IDA (and my mouth watered), but I cannot afford the price tag.
(Well, strictly speaking, I won't even try to convince my wife that we can afford it.
So, I have looked at other ways to examine the 1.01C code.
I have the 4MB (incomplete) dump - thanks to whoever created it (was it valor?)
I have created a dis-assembly file using the scripts from another developer thread here.
I have found a tool that allows me to "simulate" the execution of the program from the .BIN file - it is Crossware - Community Edition.
I set up a completely different ARM processor - using the AT91SAM9G20 - and I "skip around" instructions that are not well handled because of the different base architecture (PMU vs. MMU, for one).
I have emulated enough of the code to notice that the 4MB dump is not the complete firmware dump.
(for starters, the startup code copies code from ffc0282c through ffc2181b to location 00001900.)
However the dump data ends at ffc0fbff.
This means that there is some code missing in the dump.
Does anybody know yet how to get the remaining dump data?
I noticed a post or two that indicates that the LED dumping hangs at the end of the first 4MB. (which is what this dump essentially is)
I am lazy enough to not particularly wish to try dumping additional memory if someone else is better set up for this than I am.
I was unable to obtain the beta source code for CHDK for the FW1.00 SD980 port.
(Something about a limit on the number of downloads, or some such)
So my efforts to understand the CHDK source code have gone not very far yet.
I have tried a binary compare of the 1.00 dump to the 1.01C dump.
Much is the same, but much is also different
Quick scanning, however, seems to show most changes are simply new memory addresses for routines, etc.
This is all going to take considerable time, but now that I am started, I can keep "chugging away" at it.
Anyway, it is getting late here so I am off to bed.