Found this at http://na.blackberry.com

BlackBerry Handheld Software v4.2.2.302 (Chinese)

Package Version: 4.2.2.302
Consisting of:

* Applications: 4.2.2.122
* Software Platform: 3.4.0.24
* File name: 8707vCJK_PBr4.2.2_rel302_PL3.4.0.24_A4.2.2.122.exe
* File size: 70.57MB

I noticed my bb starts to slow down after upgrading from original preloaded OS. i have upgraded to various versions but still slow.

Is it possible to downgrade?