Hi all, I have successfully upgraded the firmware to Diablo. I used the guide from,

http://fosswire.com/2007/12/30/n800-...ash-to-os2008/

It took be hours to understand linux commands cos I'm a windower hahaha.

Anyway, here's a short guide,
1)create a folder on Desktop and save the flasher + firmware together in it
2)open terminal, type cd Desktop followed by cd "folder name"
3)type chmod +x flasher-3.0
4)type sudo ./flasher-3.0 -F "Firmware name".bin -f -R

It will unpack the files and follow the guide onwards from the website and you
are ready to rock!

Thanks for all the advices!!!