Problems with firewire. Broken in 4.8?

[Andy MacDonald]

Hi guys.
I'm having problems with firewire devices. I've extremely confident I have 
got all the correct kernel support compiled in. The fwohci and firewire0 
come up in the boot sequence. There are no devices made for either of them 
and nothing I can do will mount them. I thought it was just my 
incompetence, but my local guru now cannot mount the same drive. Previously 
he was able to with a quick flourish.
We have virtually identical Dell Laptops. The only thing different with his 
laptop since the last time he mounted that drive is that he's now running 
4.8, as I am. (previously I've never had to mount the drive under FreeBSD)
The problem is not with the drive as it works perfectly under various 
different windows versions.
Has anyone else had this kind of problem? Is there some documentation I 
haven't found yet that may offer hints? He's come to the conclusion that 
the firewire support may be broken.
Regards. Andy MacDonald