In chdkptp r924, I added some commands to the devutil module for working with non-CHDK PTP operations.
In particular, dptpsendobj allows uploading files to a camera without CHDK installed, which may save some round trips with the card reader while porting.
Note that some cameras crash if the upload file name does not include A/, while other crash if it does. I don't know which are which. A540 requires A/, while IIRC all my other cameras do not.
devutil can be loaded with
which can be included in your user.chdkptp startup file.
devutil has a number of other goodies, which aren't new but may not have been described here
dromlog downloads the romlog, automatically decodes vxworks
The dprop* commands allow you to snapshot and compare propcase values
dl* allow you start and stop UART redirect logging (on cameras that support it), and download the UART and camera logs