IONI firmware 1.6.0 beta 2 has been just released. It adds many new features, not just BiSS/SSI encoder support. For full list & download, see http://granitedevices.com/wiki/IONI_firmware_releases
Also grab a copy of just released Granity 1.13.0, which is needed for the new FW: http://granitedevices.com/wiki/Granity
We hope to move fast and make 1.6 official firmware as soon as possible so we can proceed forward with other upcoming features. Many exciting things are coming after this firmware version as well.
So, please try the new firmware and Granity and post your comments below
(edited your links to work -Mika)