ASA 640 & 1280

any chance we can get these ASA settings added... would love the option as I think 1600 is actually too far for the ursa mini.

There is no real advantage of doing so. The Ursa Mini, as do all of the BM Cinema cameras, do not add or subtract analog gain when you change the ASA/ISO, as do regular ENG cameras, and most Prosummer video cameras.

The camera's are locked to an actual ASA/ISO of 800. Selecting 1600 isva one stop gain normally, but only changes the exposure curve on BM Ursa Mini (and other Cinema cameras). So ISO 1600 shifts the dynamic range towards highlights, while ISO 400 shifts towards underexposed (blacks), and respectively, the mid grey zone sifts accordingly, when recording ProRes or DNx codecs only.

When shooting Raw, the ISO is just metadata to set Resolve or other NLE programs that can read this metadata file, you can change this setting to any point between also, so doing so is not necessary in camera.

Cheers

Frank, as Denny said - the BM cameras have no analog gain, so ISO setting is just a setting. You can jump to any ISO in post as I've shown here:
viewtopic.php?f=2&t=56353