Recently we have noticed and received request on,  “how to upgrade the BlackBerry 8520 device”.  The latest handheld OS for the 8520 is  4.6.  There are a few ” 8520 Blackberry 5.0 os handheld leaks” floating around on the net however users are reporting various problems. The major problem seems to be SMS messages. For example, messages are being deleted, messages are not showing up in chronological order..etc.  Another issue is that the BlackBerry Desktop Manger isn’t recognizing  the new handheld os software after being installed – mainly because it’s not an official supported version .

Our Lab Test: ( we don’t recommend doing this )   As a test, we were able to install Handheld OS 5.0.509 successfully. However, there were many  SMS issues that occurred.  By removing the update option under advanced options on BlackBerry Desktop Manager, this allowed BB Desktop manager to recognize the upgrade handheld os files. Also, delete the vendor.xml file and load the handheld os by using  the loader.exe or BBSAK software.  Note: If you already have BlackBerry Desktop Manger installed and configured, you “may” have to do a complete uninstall and reinstall.

Best practice : Always install and use official software released by your BlackBerry Mobile Carrier and Research In Motion for best results.