Homebrew developers LewisHamilton, PSPNerd, and Stiffmeister have released an update for the 3.90 M33 Easy Installer.

Now known as 3.90 Easy Installer v2, it has a couple of new additions that people should really like, such as additional steps to determine if you're using a PSP Slim or Phat, and if you want to add the 1.50 Kernel or not to the easy installation procedure

Here's the basic changelog for 3.90 M33 Easy Installer v2:

* 1.5 Kernel added
* Vista compatibility added
* Steps added

Note that this doesn't have a homebrew, and the developers give you a warning about the possibility of bricking your PSP via this procedure. If you're the type who wants to simplify the upgrading process, though, then you still might want to give this application a go.