The person I responded to obviously doesn't as he said F5 doesn't do internal 4K. The "paid" 4K firmware update 2 years ago was less than $1000 which is peanuts given we are talking about $10,000+ cameras. Even before that, there was hack that allowed internal 4K recording anyway. Most F5s sold today are already updated to 4K fw version, aren't they?
The point is that when C300 Mk II was released, F5 by that time, already did internal 4K. and much more (ProRes, DNxHD, HDCAM SR 422 and 444, 10-bit XAVC, high frame rates, all internally, and 16-bit raw to AXS-R5 raw recorder.)