Software For BlackBerry® Storm 2 (TM) smartphone
BlackBerry Handheld Software v5.0.0.545 (Multilanguage)

Package Version: 5.0.0.545
Consisting of:

• Applications: 5.0.0.341
• Software Platform: 4.2.0.146
• File name: 9520M_PBr5.0.0_rel545_PL4.2.0.146_A5.0.0.341_TIM_Italy.exe
• File size: 111.85MB

Note: The Software Platform and Applications version numbers can be found under Options-About screen on the handheld.

• Download: OS 5.0.0.341 for the BlackBerry Storm 2 9520 from TIM Italy
• How To:
  • Backup And Restore Your BlackBerry
  • Upgrade your BlackBerry Operating System (OS)

Please report any feedback/findings in the comments.

REMEMBER: It is recommended that you make a backup before attempting to upgrade your BlackBerry just in case something goes wrong during the upgrade process. *

Thanks @JennieBunnie!