This weekend I was preparing a .NET MF workshop and got quite a shock, when I could not upgrade my dev boards to the newest release of the firmware including do to a signage error as stated by the upgrade programm. The tool that really helped my out this time was MFDeploy.exe, which is part of the SDK tools. With it, the upgrade of the binaries on all boards worked like charm.
well, it is always good to know some friendly helpers, when You need them. 😉
Btw., the new IP/Stack in the .NET MF is quite cool and together with the DPWS (e.g. UPnP over Web Services) in Beta I see a loot of interesting usage scenarios coming.