Everytime you choose a Bluetooth device on your iPhone you see its pre-defined title which you cannot change from the handset. Jailbroken users are lucky as they can rename Bluetooth device on the iPhone without problems. For example, you need to rename Bluetooth speaker directly from the iDevice. How can you do this? Agree that it is more comfortable to know which wireless speaker to use when you have several in different rooms. Once again, you have to be jailbroken so if you are on iOS 7.1.1 or iOS 7.1 you cannot use this hack yet. To change Bluetooth device name from iPhone, follow this guide.

Instruction for Renaming Bluetooth Devices on iPhone

 Step 1. Open this folder on the gadget:
var/mobile/Library/Preferences
Step 2. Find this file: 
 
com.apple.MobileBluetooth.devices.plist
Step 3. Copy the file mentioned above to your Mac.
Step 4. Use the program called Property List Editor to launch the file.
Step 5. Launch BT MAC address and find your gadget. You can now set a new device: use “Name” instead of “DefaultName”. Save the file once again on your Mac.
Step 6. Now copy the new file to your iPhone. Just overwrite the old one.
Step 7. Reboot your smartphone.
Step 8. You have finished renaming Bluetooth devices from iPhone. When you wish to change the name once again, just edit this file and you’ll do all right. Thanks hondavtec user from iPhonewzealnd for this guide.