3G upgraded to 4.2.1 now browser crashes

[Opolisyis]

I upgraded 2 different iPhone 3G devices to 4.2.1 and baseband 06.15.00 according to this guide (http://www.redmondpie.com/how-to-update-iphone-3gs-3g-baseband-to-06.15.00-with-redsn0w-0.9.6b5-for-ios-4.2.1-unlock/) and now both of them are having the same problems.

Safari (among other things) is crashing springboard and sending it into "it Safe Mode". When they are connected to the edge network (we're using Tmobile) we get a page that requires us to pay for web access. http://i.imgur.com/I1gIz.png in this example I visited google.com and was sent here.

I know it's not their plan because we share a plan and my iPhone browses the web on edge fine.

Can someone send me in the right direction at least? This happened to two different 3G phones, I'd be surprised if this was an isolated incident.

[iYeow]

Shift + restore back to stock 4.1, use Exit recovery from TU when error 1015 popa up.
Jailbreak your IOS 4.1 with Redsn0w 0.9.6 and unlock with Ultrasn0w .

[eelpout]

Glad (sort of) to see others are having Springboard crashes since going to 4.2.1. I thought mine had been because of Switcher Mod/Remove Recents, but removing them hasn't made things any less crashy. I used the latest Pwnage tool to JB and have a 3G.

For me, trying to open any map link from within an app (like Yelp's "Directions to Business" for instance) pauses the iPhone for a sec and then crashes Springboard. Is there any way to double check that the map link is accurate in a pref file?