O.K., so I want to upgrade to the 2006 OS.
I have a wireless network at home, DSL, dual boot notebook with Windows XP (no service pack), and Linux (Suse 9.1), and the 770, so I feel reasonably well prepared.
I go to the download site http://www.europe.nokia.com/nokia/0,,79636,00.html
and download the update Wizard Nokia_770_SW_Update_Wizard.exe

Run it and it tells me that as a prerequisite it needs .NET 2.0, so I get that from Microsoft.

Run it and it tells me that as a prerequisite it needs a Windows updater tool (I forgot the exact name), so I download it.

Run it and I'm being told that as a prerequisite I have to allow active X, and run the Genuine Microsoft software.

I am cautious ( http://windowssecrets.com/comp/060615/#story1 ). My notebook is not that powerful, and I took me quite some effort to tweak it and get rid of all these extra processes, calling home, switching on the hard drive wasting battery, etc., and make it running smoothly. I'm asked again if I want to install something, I click on no, but it still starts to install something, fortunately one of my security tools pick it up. So I decide to abandon the Windows route. I don't trust them. All my tweaking efforts intended to get a smoothly running machine would be lost. Something quite intransparent is going on.

Another route: O.K., I have Linux (Suse). Unfortunately, since I upgraded to DSL and wireless, I can not connect any more. No problem, I boot Windows , go to http://maemo.org/downloads/nokia_770 and get the big image of the OS 2006, then to http://maemo.org/maemowiki/HOWTO_Fla...ImageWithLinux , from there to http://maemo.org/downloads/d3.php and try to download the flasher - actually I need the flasher 2.0. I confirm the EULA, and nothing happens ;-( Is there an autodetection finding out that I am trying to download Linux code using a Windows machine?

I give up and go to work. From the company PC (also Windows XP, I have no admin rights or else), I can at least download the Linux flasher2.0 . I'll copy it to my (private) notebook later, and I'll see what will happen when I try to run it on a locally running Linux.

What I don't understand: Why all that heavyweight fuzz - Wizard, Service pack, dotnet 2.0, etc. etc. when all I need is a flasher tool, which has only one purpose: to get the image file from the PC, through the USB cabe, to the 770?

Reply to self:
so I downloaded the flasher 2.0 at work to a USB memory stick. At home at my private notebook, I booted Windows, copied the flasher and the big binary image to C:/ (just to find it more easily), and renamed the image file to OS2006.bin in order to avoid typos later at the command line.
Then booted Linux (at the PC), started a console as root, went to the WIndows partition, and followed these instructions: http://maemo.org/maemowiki/HOWTO_Fla...ImageWithLinux
Did not work, even as root I did not have the permissions. Thus I copied the two files from the Windows partition to the Linux partition, and executed the flasher 2.0 calling the file I had renamed to OS2006.bin including the appropriate parameters.
And: just as promised, it worked.

Conclusion: it's not yet fool-proof, if you don't have the latest software. But taking into account Nokia's focus on consumer products, I assume (and hope) that they will be able to provide a simpler way to upgrade from any platform. Ideally (OS2007?) : using ONLY the 770; download the next binary image to the mmc, having a flasher app running on the 770, and rebooting from mmc. This would avoid all issues with Mac, Linux, Windows, Vista(?) flashers.

Side-track: thanks for the private message; no I most likely don't spead viruses by not having the service packs; I manually installed all patches directly from Microsoft while this had been possible, and I have other security tools, and a secure DSL router.
It's about control: I want to be able to decide, at least in principle. To use an example from my industry (pharmaceutical): Patients participating in clinical studies before the drugs are approved by FDA or other authorities have not studied medicine, they are not experts; nevertheless, they formally agree to the treatment. They are in a weak position, compared to the doctor or pharmaceutical company, but they collaborate based upon the notion of "informed consent". We have to make sure that they understand what is going on. Which is ethically O.K. and different from attempts in the Software industry to disempower the individual by legal (endless EULAs and other conditions) and other (e.g. secretly installing spyware) means.

That's one more reason why I like Nokia's approach. In my case, it's not about free = zero costs, it's about the other meaning of free.

Side-track to the side-track : I totally agree with Christian. My DSL router blocks all incoming traffic to my network except for a few ports on a Linux box. I also NEVER use Internet Explorer or Outlook Express or MSN or any other such MS network app on my home machines. Given that, I have had a long list of 98-then-XP machines without patches, SPs, updates, or problems. And I'll rather switch do desktop Linux that let that WGA stuff in.