A short follow up to the earlier N73 update post. I was able to find a copy of XP and installed it on a old Athlon XP machine. First the updater just froze and I was already sure that I now have a nice black brick, but fortunately the phone booted with the old firmware still intact. Ok, second try: This time the update was uploaded properly and my phone was running the latest firmware. Oh joy! :D
But wait.. all didn't go well at first.. Nokia data restored ok, but after restarting the phone a got message like this "Phone startup failure." and it froze there. Fortunately a quick google found a "4 finger salute" reset operation that fixed the bootup. And skipping restoration of my previous settings made the phone finally work OK.