anyway you can try to apply original canon update to your cam twice before applying hacked version
Just to point this out: when I now update to 1.0.5 (30D), it seems to start up "another application" called "Firmware update program" - so it is possible that this is actually some standalone updater program. But it seems like you must have the actual firmware running to invoke this application. It states "Firmware update program\n<line>\nUpdating now.\n<progress bar>\nX% done.\nWarning DO NOT turn off the power switch or touch any buttons!". Then it states Update complete 1.0.4->1.0.5. I hit ok. It then says "Please turn off the power switch and reload the battery.".
if camera accepts update with the same version it is safe to try experimental update and later revert to original one ( assuming new one is made correctly. and this can be confirmed by independent "experts")
Actually, I didn't think it would, but it does! It asks "Update? 1.0.5 -> 1.0.5", and apparently happily flashes the whole thing again.
Somewhat scary that you write "experts" in quotes!!
How is this process doing? How's your experts doing? I'd be willing to check out your fix, if you showed me the code and walked me through the actual changes.