Hi, I'm in Australia and work mainly in remote mine sites. I have an Optus branded, unlocked X10i that I just received from insurance because my old phone (Nokia N95 8GB) died. The thing is that with both of these phones I use a Telstra prepaid sim card in them and on one site I frequent there is no service from either of them. The sim card works in all other phones. The same happens with all Optus post-paid phones using Telstra Next G sim cards, regardless of the phone brand so I assume it's in the Optus firmware. However the debranding tutorial here in these forums describes a folder on "C" drive that does not exist on my computer. There is no folder "Update Service" or "db". Firstly, would debranding the phone help in my case an secondly why is there no such folder? Thanks. btw. I am a novice.