Couldn't find the official correction in the code - is this already done?
The problem is affecting multiple cameras (see for example the A495 issue in the German forum).
My bugreport was this:
http://chdk.setepontos.com/index.php?topic=265.msg79397#msg79397The fix is part of waterwingz's rework of the usb remote functionality, read from here (there are issues surrounding it):
http://chdk.setepontos.com/index.php?topic=7127.msg79948#msg79948Note the "platform/camera/kbd.c changes" part in waterwingz's post.
The problem with the A430 port (and the timing of my patch) is following:
- My patch changes the A430 port to use the common keyboard code that is used by a number of old (DIGIC II) cameras.
- The above initialization code is in that common code and affects those models. My revised patch that fixes your ptp-script issue includes changing that common part. I don't know whether it would be accepted.
I'd like to continue the testing of the A430 port.
Feel free to do it

The noticeable changes are the following (between the official version and the patched one):
- histogram, zebra: now displays correctly in play mode (was rubbish before)
- raw numbering fixed: without the fix it is always one less than the jpeg
- modemap corrected: setmode.lua crashes the camera without the fix
- usb remote: with enabled usb remote option, it should now react to a plugged in usb-cable
- some corrections in capt_seq.c: the only visible change is that without the fix, Tv override has no effect when the lcd display is turned off
- added keyboard initialization should prevent scripts failing when started over ptp on a recently switched-on camera
Let me know, if this is unclear (I tend to get tedious).
Attached are updated patches for CHDK stable and CHDK-DE.
edit: The changes got accepted into CHDK.