Orange 2G never works

Hi,

I've had several iPhone 3G's to unlock and I've tested to see if most of the popular Network Carrier's work with it. All of them did with no problems apart from Orange 2G, I tried with mine and it kept saying "SIM Invalid", at one time it worked, but when I rebooted it went back to the same error. I tried loads of commands in Terminal, it fixed it temporarily and then went back to the same again. Once I was lucky, I just tried my 8 year old Orange 2G SIM Card and it worked! But after a couple of reboots, it died. Any idea on this? As it seems to be the same problem on all the iPhone's I have tried.

Regards,
Neo-Tech

I should enlighten that I am on the O2 network and on 2.2.1. It's got to be a problem with yellowsn0w as it's other phones that don't work too.
I used commands like -r -y etc

Surprise, surprise! I tried again today and it worked! Then I tried another one and it didn't work :( There must be something in Yellowsn0w which causes this, could I get it to log everything it does?