O2 has ultimately launched the windows Mobile 6.1 update on behalf of the XDA Stellar aka HTC TyTn II.
You shall require to have an O2 mobile to be able to access the download page: http://www.my-xda.com/software_updates.jsp
The install process is straight forward.
Download, plug in your PDA to your PC. Establish a connection active sync (XP) or sync center (Vista). And jog the file. Its as simple as that. Oh yeah, dont forget to back up your files as everything on the PDA’s onboard memory shall be wiped out. The process takes about 10 minutes.
I have not idea how to execute this using linux. I guess that using WINE to emulate active sync as well as jog the updater should work, but I haven’t tried it. If someone has tried updating their PDA using Linux or different platform, please do let us know the steps as well as the results.
Thanks!