BBLeaks has come across OS 5.0.0.612 for the BlackBerry Storm2 9520. you can download the OS from the following link:
http://www.multiupload.com/44F2L0QS34
WARNING: This is not an official OS release, install at your own risk or start by reading this step by step guide. NOTE: Don’t forget to delete the vendor.xml file located in c:program files>common files>research in motion>apploader to install it on a different carriers device.
Let us know in the comments if you find any problems or new features with this OS.