First, if you're new to BB or you've never made modifications to your BB before then this may not be the procedure for you. However, if you're familiar with the BB and it's OS and have edited made modifications, such as for themes, then continue on.
If you're like me and you never use the VAD installed on all the new BB's you can remove it and free up over 1/2MB of memory on your device. Also, some have complained that their BT headset keeps activating the voice dialing menu when they don't want it to. There's no way to disable it on the device but it can be removed by removing all the modules associated with it.
Remove the following .cod's:
net_rim_vad_engine_resource__en_US.cod (this is the big one that's over 1/2 a MB.)
If you have other languages installed you will have other vad.cod's installed that you'll want to remove.
You can do it with javaloader (if you know what you are doing) or you can remove it the same way you would any vendor themes you no longer want.
Install Desktop Manager to the PC. Get it here
Install to the PC the OS package that matches what is installed on the handheld. Find your OS here
Then go to the java folder for the OS and rename or remove all the net_rim_vad.... cod's
The java folder will be located here:
C:\Program Files\Common Files\Research In Motion\Shared\Loader Files\8320-v220.127.116.11_P18.104.22.168\Java
(note: your BB model and version number may differ from mine but will be located in the same place.)
In my case I simply renamed them like this: "REMnet_rim_vad..." but you can move them to another folder, or even delete them, if you like. You can always get them back again by running the OS installation package on your PC again. It's just easier to get them back if you don't delete them.
Then run Desktop Manager and Application Loader. Nothing will show as needing an update in the main window with the checkboxes. However, just finish the apploader and you will see that the vad cod's will be removed. The device will reboot and you'll have no more VAD.
Disclaimer: I take no responsibility if this totally breaks your phone or if it blows up into a gazillion pieces after modifying in this manner. Warning: Removing the VAD .cod's on 4.3 and newer OS devices will render the Options >About screen inoperative. Everything else seems to work fine except for this. You can still use alt + eace to get the same information. Note
Here's another good post about removing other items and optimizing your BB's memory. Click here