I got one of these about 6 months ago but only recently started messing with it. I wanted to make sure my firmware was up to date so I started reading up on how to update it and quickly hit a brick wall of confusing, outdated and obsolete information.
Updating the FPGA bitstream (to v3.07) seemed okay but trying to update the PIC code was not working at all for me.
Here is the best guide I've found: http://samelimmat.blogspot.de/2013/05/open-bench-logic-sniffer-with-os-x.html
I did this on linux. The problem is when you go into update mode, the /dev/insert-your-usb-device-here goes away after a few seconds so passing it in on the command line is problematic. I discovered that if I got the command line ready, and then went into update mode (by holding down UPDATE button and pressing RESET) that the /dev/insert-your-device-here would stay resident for a brief period and I could quickly run the command line. It worked!
See http://www.mikrocontroller.net/topic/264866#2759493 for how I got /dev/OpenLogicSniffer
The exact command line I used:
sudo /home/matt/ols-fwloader/bin/ols_fwloader -f BOOT -n -P /dev/OpenLogicSniffer -V -W -w OLSv1.firmware.v3.0.hex