I don't actually have the 24, just the 18, but it should be the same firewire chip. There's no reason it shouldn't behave identically to the HelixBoard 18, which has been working flawlessly for me for some time now. Not sure if Phonic changed anything for the MK II's though, so this functionality is only confirmed for the original issue.
I've been using this for some time now on various flavors of Ubuntu. Should work with any properly configured freebob aware Jack install. Seems to work flawlessly. The same is almost certainly true of the rest of the HelixBoard line.