These firmware files are for the Hauppauge PVR150 capture card, they differ 
from the atrpms rpm: ivtv-firmware-20070217-13.at.rpm

The problem I was having were glitchy frames, especially when there was
much blue on screen, which happened worst when changing channels on Sky.

Stick a copy of *.fw in /lib/firmware/ and reboot or:

  service mythbackend stop
  rmmod mythtv
  rmmod cx2341x
  rmmod cx25840
  modprobe ivtv
  service mythbackend start


These work for me but I hold no legal liability if these destroy your
MythTV system, software _or_ hardware - they are firmware files after
all.

Good luck!

Teschi
