As noted in the commit log, this patched made the battery door hack no longer hard coded. I added the OPT_RUN_WITH_BATT_COVER_OPEN to the corresponding parts of boot.c, so people not using the hack won't get the boot delay.
My patch did not do that so I assume you made that choice? I guess it's fine for "standardization" but it will make things a little harder on script writers if they haven't figured out how to use chdkptp to xfer script files. It really does not "cost" much to build it in and it does not really work in a non-standard manner if you don't actually use the feature.
The patch also removed some code involving altDownTimer in kbd.c. I'm not clear what it did, but figured I'd mention it in case you didn't mean to get rid of it.
My bad - in converting everything to match the other ports revised code I missed this.
The Canon firmware for the ixus120 (and I presume some other cams) natively allows you to "short press" on the DISP key to change view in playback mode and "long press" to change display brightness. Prior to us standardizing somewhat on the PLAYBACK key as the ALT key, the ixus120 used the DISP key for ALT. So that bit of code allowed a click to enter ALT, short press to toggle playback display mode, and long press to toggle the brightness. Useful but again not "standard".
Not sure how to handle this (or how many other cameras could use this)? Build as a custom kbd.c or modify the standard my_kbd_read_keys() to allow this as an option?