K3 question

I have just bought a K3, I was intending to get a K5iis, but got the K3 for only £50 more, so it seemed daft not to buy it.

After fiddling with the settings, it asked me for the focal length of the lens that was on it. I changed lenses and the same thing happened. After resetting everything to default, it recognised the lens again. It's not happened again, and I've updated the firmware. Does anyone have any idea which setting wold have caused it to not recognise the lens? The only thing I can think of was that I enabled lenses without aperture rings.

Think I found what happened on another forum- it seems with version 1.0 of the firmware, if you selected the option to use the aperture ring, ie to recognise lenses without an A setting, you had to input the focal length of the lens. .