Here goes...
I have a K100D version 1.00 I use for daytime photography and a K110D version 1.02 I use for astrophotography. I have never bothered with updating the K100D since I only use 2 GB memory cards and I don't want to mess with success.
I have consistently found Pentax Remote Assistant V 1.00 (the istD version) recognizes the K100D and functions (with a few gotchas). R.A. almost never recognizes the K110D (attaching the K110D creates a disk drive but R.A. comes up grayed out).
Of course, the one I NEED Remote Assistant for is the K110D to make focusing a telescope easier. I've given up on waiting for Pentax to provide a supported R.A. for their K1x0D and istDL customers. They don't seem to care about us.
First Question: Those of you who have found R.A. 1.00 works with your K1x0D, what version firmware do you have? I'm wondering if the older firmware works better for this one feature or if I have a coincidence.
Second Question: Does anyone know of a copy of K1x0D firmware 1.00? I have not found older versions on Pentax and other web sites.
Third Question: Does the firmware upgrade procedure work for downgrades?
Since my K110D is filterless I value it rather highly, I don't want to brain dead the camera by downgrading. But, I really would like to have R.A. work on the K110D.
