hi all
as you all know the new firmware version is out (v40).
so you have 2 option, wait for OTA release or flash it from pc ( NSU is stupid as the brick, so you have to use service software ).
there are more tools which you can use to make the update, you can find more here :
(Phoenix tool advised to use)
Offline-Flashing-Upgrade-Nokia-Firmware-Tutorial
Phoenix-Service-Software-2009-34-7-40015-Full
Flash Your Dead 5800/any BB5 phone using JAF tool
you need to get the firmware from www.blue-nokia.com
you can also get the firmware using navitool, but you will need files that navitool doesn't get.
Personally for me it took more than 12 hours to find the right software, and to make it work.
i even did the instalation from win xp in virtual box. (you just have to be carefull to connect the usb device each time the phone usb changes its profile, this happens 5 times, anyway it is a pain in the but, but finely it works and there are nice improvements).
good luck to all the people flashing devices out there.