XDA Forum user hacks to Enable A2DP BT Protocol on WP7 for Video
In simple words it means that using the hack you will be able to listen to audio of videos like on YouTube or a video on your windows phone stored in your sd card when connected to the Bluetooth headphones which are restricted only for making hands-free calls.
This has been tested and said to be working already on Samsung Omnia 7, HTC HD 7, LG E900. LG devices have inbuilt registry editor so you can skip installing WP7 Root Tools. Thanks to sunnyo_ola @ Official Thread here
Unlock Your Phone :
- Unlocked Windows Phone, You can use Chevron Unlock which is a cheaper tool. You make sure you backup your windows phone first.
- You will need to deploy the Install wp7 root tools to your Windows Phone. This will help you change the registry settings.
- In case you get an error 0x81030120, I will suggest you to install the Internet Connection sharing app which also disables the Interop Unlock issue which gives this error.
- Using WP7 Root tool you need to change registry key value dword value DisableA2DPPLayback from 1 to 0 which you will find at Local Machine\Software\Microsoft\Zune\Playback\Video\A2DP\CapsSet1
- Done this shutdown your phone and restart to check if the value is 0 or 1. If it is 0 you are ready else you need to do it again.
- For LG Qunatum users it has been reported that the value was 27397520, according to the user who tested it, said to set the value to 1 first and then reboot to change to 0 and then reboot immediately.

Done that connect your Bluetooth audio device with your phone and watch a movie leaning back.
