I used VMWare. And no, just attaching the "new" USB hardware to the guest was not enough. iTunes only saw the iPhone if the Linux host did not have the USB modules loaded (and in fact had them blacklisted so they wouldn't be loaded automatically either).

It is (or was, don't know, this was about two years ago) a known problem: http://www.ivankuznetsov.com/2009/10/upgrading-iphone-firmwa...