AV.io 4K highest res 1920x1200. USB2 limitation?

Hello.

AV.io 4K with Ubuntu 16.04 on an older laptop with USB2 ports.

Using utils like v4l2-ctl and qv4l2 I’m only able to set the resolution of an AV.io4k
to a max of 1920x1200. A request for available formats does not list 3840x2160.

Input signal is 3840x2160x29.97. Despite the mismatch of signal to AV.io4k resolution, I’m able to capture and save an image at 1920x1200.

Why is 4K not presented as an option? Is it because the AV.io4K sees that the connection is USB2 and reacts by limiting bandwidth? Is it something else?

TIA
SJM

Resolutions higher than 1920 X 1200 require USB 3.0 connections unfortunately.
USB2 also has its own limitations: inconsistent and low frame rates at HD resolutions, embedded audio is also usually not present