Hi Ccchiong,
Regarding the message SW upgrade I think it is a normal message, when you reboot you will reboot to the software version you have installed on your Elgar/verdi.
If your stack is "old" and you have not upgraded the software it could be an idea to contact a dCS dealer to get the newest software for your stack.
Regarding 176 k data I was using this in master mode on my purcell/elgar when I had a problem with 1394, I think if I remember correct that you then also have to set something in the menu in the purcell, but memory here is a bit fading out now.
Regarding 1394 cable, I think you know can get them relatively cheap from a aftermarked cable supplier or contact dCS, I will be surprised if they are expencive
Kind regards
Geir
Norway