[mythtvnz] MythTV no longer recording TV (after update?)

[lists at whitehouse.org.nz]

Hello,

I use Mythbuntu 11.10 (and have done for many years).  When I tried 
watching Live TV this morning, I realised that MythTV is no longer 
recording television properly (without giving an error). It was working 
fine yesterday morning. My old recordings are working fine, so my guess 
is that it is on the capture side of things.

I use an HVR-2200 (same as an HVR-2250 for PAL) with Steven Toth's 
driver/firmware.

I have seen a bit in the news about the updates for the Linux kernel 
vulnerability:
http://www.ubuntu.com/usn/usn-1336-1/
http://www.itworld.com/244019/linux-vendors-rush-patch-privilege-escalation-flaw-after-root-exploits-emerge

I have automatic updating turned on for security updates, so I'm 
wondering if perhaps the kernel update could have somehow broken the 
firmware? This does seem a bit unlikely for a security fix, but it is 
the only big update that I can see.

If there is an easy answer, it would be great if somebody could give me 
some pointers before I lose hours trying to locate the problem. Nothing 
jumped out at me in the logs before I ran out to work.

Regards,

Aaron