The update will preserved the baseband from getting upgraded so that it can be unlocked using Ultrasn0w. Sn0wbreeze 2.7 also supports iOS 4.2.8 for Verizon iPhone.
Sn0wbreeze is considered as the unofficial PwnageTool for Windows.
SnOwbreeze will allows users to create custom iOS 4.3.3 or iOS 4.2.8 firmware file that is pre-jailbroken and that can be used to upgrade their iPhone, iPad or iPod Touch to iOS 4.3.3 or Verizon iPhone to iOS 4.2.8.
Well in case of iPhone also it preserves the baseband from getting upgraded so that it can be unlocked using Ultrasn0w.