Enable hidden folders as mentioned in my other listed FAQ or use the Dashboard Widget "Show Hidden Files" to do it.
Navigate to the hidden folder named "iPod_Control", and once there click on the folder "Device". Once there, delete the file named "_volumelocked".
Eject your iPod. Then, restart your iPod. You can do this by holding down the centre and menu button for at least 6 seconds.
Once your iPod has rebooted, check and make sure that it worked. Simply go into "Settings", "Volume Limit". If it asks for a PIN, you did it WRONG. Retry the above procedure.
Unlock iPhone Volume Limit
Enable hidden folders.
SSH into /System/Library/PrivateFrameworks/Celestial.framework
Backup the file regionalvolumelimits.plist to your desktop.
Delete the file from the iPhone.
Reboot iPhone - and you're done.
To re-instate the limit simply copy the file back into it's correct location on the iPhone
ALTERNATIVELY, simply open the file and change all the values from 0.83 (i.e. 83%) to whatever you want, e.g 1 (100%) or 25 (125%) and save - although this may not work on newer firmwares.