The new bootloader that ships with PR1.2 includes new 'security' restrictions that mean that a number of operations will exit trusted mode, triggering a disclaimer message whenever you boot the phone.

Do not load any third-party kernels using flasher, such as the "rescue kernel". Doing so will set an "untrusted" flag that can only be reset by reflashing the phone, clearing all user data.

The one exception is if you wish to use open mode - this is an easy way to enable that on PR1.2. However, this should only be done immediately after reflashing the phone.