Back in June when "Mango" was first making its rounds, one of the first things we noted with regret was the inability to sideload pretty much all homebrew apps created up to that point. What would happen is you would try to load the app and be greated with "Error 0×81030120". Reason? It's technical but "Mango won’t officially support the deployment of custom applications with the ID_CAP_INTEROPSERVICES capability flag".
Even more of a bummer for the proposed ChevronWP7 Labs, which would be limited to sideloading only apps that don't modify the registry--that is, apps that can't customize the OS at any level.
The good news though, as reported by ChevronWP7 member Rafael Rivera, is there is a way around this. XDA member“Heathcliff74” discovered that if your MaxUnsignedApp value is 300 or higher, you can remove the limitation and sideload the app. This gives devs an easy workaround for re-enabling Homebrew apps (it's been speculated that this "trick" was for MS employees and OEM partners).
Rivera goes on to state "The suitable pairing for this hack is, of course, ChevronWP7 Labs". That's of course, some great news for all of us.