I don't really understand why there is so much discussion about assigning blame to the firmware. To use an analogy to Windows...
I have a desktop that is ~6yrs old (self built and upgraded in that time) and a laptop that is ~2yrs old. At this point, I have Vista on both of them and they work fine. However, sometimes (at most once/week) my desktop resumes from sleep and blue screens. This never happened with XP and it never happens on my laptop (with Vista). Now, if separate people owned my two computers, the desktop owner would say, "Vista is crap and broken b/c it blue screens", and the laptop owner would say in reply, "mine never blue screens, so it's clearly not Vista".
In the end, I do believe that it's Vista's fault (although I don't think it's crap like many people like to say nowadays). I think it is impressive in general that Windows supports so much hardware, but it's obvious to me that my desktop's older hardware just doesn't work as well with Vista. However, Vista should still be designed to support older hardware and work around any quirks, even if it's the hardware's problem.
My point is that just because some people have working Shareport with the latest firmware doesn't mean that the firmware is just fine. Obviously us users who have this Shareport issue have something in common that the new firmware is not agreeing with. Regardless of whether it's actually caused by a particular network configuration, usb device, hardware revision, etc, the fault must lie with the firmware. If, without changing anything else besides upgrading the firmware, functionality is lost, then the new firmware is to blame, plain and simple.