For use with any of our products (old or new, USB 2.0 or USB 3.0), when connected to a USB 3.0 port, even if only to operate at USB 2.0 speeds, we recommend kernel 3.4 or newer. That is because USB 3.0 ports use the xHCI kernel module, which has an issue with queueing large transfers in order kernels. That does not affect eHCI host controllers (USB 2.0 ports); however, the eHCI kernel module cannot be used with a USB 3.0 port, even if a USB 2.0 device is attached. We are working on a workaround, which will be included in the next release. We will publish an article with instructions to use it once it's released.