Back in June, I noted changes in Mango that prevented the loading and installation of applications that required use of the ID_CAP_INTEROPSERVICES capability flag. Today, Windows Phone enthusiast “Heathcliff74” bypassed that limitation for the Samsung line of phones, using its OEM-ware to his advantage. The trick? He discovered that if your MaxUnsignedApp value is 300 or higher, the limitation vanishes. (It’s very likely this was meant as a backdoor for Microsoft employees and close partners.)
The suitable pairing for this hack is, of course, ChevronWP7 Labs (when it becomes available).