Hi, I'm working with a US iPhone 4 that's been updated to 5.0.1. I've been trying to get it to work with a European SIM card here in the Netherlands (the carrier? Hollands Nieuwe). I've tried jailbreaking it with Redsn0w and running Ultrasnow. No matter what I try, the phone refuses to let go of my original carrier (AT&T) and continues to give me an "invalid SIM" message whenever I try to use the new one. I also tried limera1n, which caused the phone to sputter out. I wound up running a restore via iTunes to bring it back to life. Any advice about what to try from here would be greatly appreciated. Thanks!