http://www.digital.pentax.co.jp/ja/info/20070123e.html
Pentax Japan released a minor firmware upgrade for Pentax K10D digital SLR. What's new:
- Correspond to development in the RAW data camera when multiple exposing.
- When built-in flash is used the luminescence control by the trailing-shutter-curtain sync was corrected.
It's hard to understand what was really changed, but I think that it should fix the bug with flash synchronization appeared in some conditions (some people reported that the flash fired twice at long exposures).
You can download firmware upgrade at the page linked above.