Apple has released a new version of the iPhone SDK, this one labeled build 9M2158a, beta 3. The previous build was labeled 5A225c.
We're not yet sure what's included in the new release, but we are receiving reports from developers indicating that iPhones legally running the pre-release 2.0 beta software, build 5A225c, were been remotely disabled by Apple and can be restored to full functionality using the new build of the device-installable OS -- which is labeled 5A240d.
Apple's notes, according to developers, state that the SDK update "fixes bugs and adds support for the latest iPhone OS."
Regarding the remote disablement, Apple's documentation states: "Once you install the pre-release iPhone OS on your device, such device may only be used for development and testing purposes until the final (GM) version of the iPhone OS is released. In addition, you will need to install new versions of the software from time to time throughout the beta period. Failure to install the most current version will, after a period of time, put your device in a deactivated state."
iPhones that are unlocked and "pwned" are not subject to Apple's remote lockdown.