Another official update was just released on HTC’s website for the HTC HD2, again, addressing functionality.
“This update for HTC HD2 enhances the native Car Kit Mode functionality. This update includes the ability to allow the phone to stay natively in Portrait mode so you are given the option of flipping to a horizontal view or staying vertical. Also included are call history view expanded, allowing the dialer to dial “+” in the recent call menu, and providing more flexibility in completing messages while using Bluetooth”.
Download and copy the EXE file to your Device, run it and perform a Soft Reset after finish.
Note: You will have to reapply this update if you perform a Hard Reset.