I've been using an ASI1600MM with EFW8 for some time, and until recently it always worked perfectly (well, after I changed the T adapter to one with shorter threads so the Astrodon filters didn't hit it). Recently, it seems to have lost its mind, selecting filters other than what I wanted. Experimentation suggests that it somehow believes it is a 5 position filter wheel! The advanced setup (using ASCOM driver) shows only the first 5 positions, as does TheSkyX (suggesting that the hardware is reporting itself as a 5 position wheel). I mainly use Maxim DL for capture, and it always allows selection of more filters than are actually present or supported, but selecting any position greater than 5 is just ignored. Worse, even with the first 5 positions I don't always get the position I want because the firmware seems not to care very much about the index signal that marks position 1 - most moves are just relative to where it thinks it is. The only exception is that if you select a filter that causes it to land on position 1 (when that was not expected), it sees the index mark, changes its mind about what the current position is, and does another relative move to get to the position you requested.
Has anybody seen this or similar behavior? Is it possible to re-flash the firmware in the EFW8? Could something else be wrong?