I am not sure I am a good source advice given my newness to the phone and my inability to login as root (bought from Carphone Warehouse) to see what is there and what is not. I was also unaware that there was an upgrade until the end of next week or the week after.
If you have done nothing to void the warranty, I would suggest returning the phone to the shop and replacing it with another one. If you have made modifications to the administrative system then it may help others to know what. It may also be helpful if you can state what lg hardware you can see, confirm the absence of the lg modem driver, what happened when you pressed the key combination, how long you waited after the apparent stall, etc...
I appreciate that this is only general advice but it may help others that know more about the situation you are in to give you pointers.