Not getting any answers to my question, I experimented using some of the existing information. It turns out that the instructions posted in PF for debug on the k200d worked for my k100d super, except that the modset file needed to be renamed modset.459. With that change, these instructions worked for my K100d super:
https://www.pentaxforums.com/forums/pentax-dslr-discussion/75223-k200d-autofo...ne-tuning.html. Read all the related posts in the thread to get a good sense of what's involved.
For hman's question on K100d non-super: I don't have that camera any more, and so can't repeat what I did. But there are a number of posts on PF regarding how to use debug in the K100D (not super). Someone's got some instructions posted in the "K100d Tips and Tricks" thread; there probably are others, and I'm not sure which instructions I followed (if there are any differences). For K100d not super, it involves a succession of button presses (rather than a special file on an SD card). I suggest reading multiple threads/posts on this to make sure they're consistent, so you don't end up ruining your camera due to someone's typing error when posting.
Do use care; if you make a mistake trying to use debug, you can render the camera inoperable, with a very expensive repair bill. I don't do this on my fairly new and still under warranty K-X, only on an older, cheaper body.