Hi,
After much research and dread, I managed to update my Virus B to 4.9. yesterday. I thought it was going to be tricky but was pleasantly surprised how easy it was when you have everything in place.I used a NI Komplete 6 interface, connected to Virus with MIDI in/out cables.
1. get the correct update file from Access.
2. drag the file into Reaper.
3. reduce BPM to about 40.
4. turn synth on
5. play the file.
6. you should see the synth counting the files as they load.
7. follow the prompts and store the files.
8. power on, OS 4.9, voila!
Hope this helps someone else.
Peace.