Thank You Very Much. Your information solved my issue.
Here's the process I used:
- From the CHDK menu, call Miscellaneous stuff -> Debug parameters -> Create card with two partitions
- Remove the card, use a card reader, format it, now you can access the first (2MB FAT12) partition
- Copy the files DISKBOOT.BIN and PS.FI2 to the root (or unzip the whole CHDK package)
- Now make the card bootable - this can be done either on a PC using a card reader (e.g. with Cardtricks) or
with CHDK (start manually, then call "Make card bootable..." from the "Miscellaneous stuff " menu)
- Lock the card, CHDK should autoboot now - you can also start CHDK manually again...
- Call "Swap partitions" from the "Miscellaneous stuff" - "Debug parameters" menu
Now the "big" partition is the first one an can be accessed...
- Format this partition using a card reader (NOT in the camera !), unzip CHDK to the card
- Start CHDK manually, then swap the partitions back.