Wab Version Changer v0.1
Great news from Yoshihiro and Wab. Yoshihiro has just released a program that will allow you to run games requiring a firmware update, without updating! This program will trick your system into thinking that it is a v1.52 system. When you run the program you will be able to check your firmware version and it will say v1.52. You will still be able to launch eboots from your memstick (such as the version changer etc?), and you can change it back to 1.50 when you are done. This program does NOT update your firmware. In fact, you will not be able to run the 1.52 update with this program enabled, as the system thinks that it is already 1.52. You can get it at http://files.pspupdates.com/cgi-bin/cfiles.cgi?0,0,0,0,21,1151, I have not tried this so if you do tell me if it works thanks
It's homebrew, so it doesn't work on 1.51-> There's also a new version of this homebrew, it can trick the version to 1.0, 1.52 and 2.0. I don't see why people would wan't to trick it to 1.0.