Way back when... when I tested a number of these 2 years ago, I found units that worked and units that didn't work. I ended up giving up my own, as mine was in the category that didn't work.
The randomness of this was also a bit off-putting. It wasn't the firmware version alone that decided if this was a working or non working specimen.

If I rememer correctly, the way to make the non-working specimens go "bad", was to open up the iris fully through metadata-control. As long as I didn't do that, it worked.

For the ones I tested, taking the lens out and putting it back "solved" that. But that's not really an option in many situations.