Many of the apps in the app store are requiring 3.1 to purchase them and I haven't upgraded because I dont think there is an unlock available for my 3G. So I used fw changer to change the firmware so I could download the apps and in the past this has worked, I was able to use the apps with no problem. However this time, any apps purchased that required 3.1 will not load on my phone. I was wondering if there was a difference or change in this firmware that affects the apps performance?

Thanks for any help