Can I still Upgrade my 2G to 2.0 if I now am using my 3G?

[moviecouple]

I had an activated 2G iPhone that was done through AT&T. I then went and got a new 3G iPhone. When I dock my older 2G iPhone... it asks me to activate again. I can say no of course and get into the phone itself... but can I upgrade to the new 2.0 firmware?

Right now I am on 1.14 and can use the SIM card from the 3G and place it into the older 2G phone and use it with no problems. "If" I can upgrade to the 2.0... will I still be able to use the phone part too?

 

[kevo0822]

I updated my old 2G iPhone to 2.0 with my old sim card in it. Once 2.0 booted up, I just switched out my old sim for the new one so that I could activate the phone and iTunes and make sure that everything was working alright.

 

[andyblila]

I updated mine with no issues.

 

[moviecouple]

So, should I leave the 3G SIM card in the 2G phone when I try to upgrade... or take the SIM card out and then try. I don't have the old 2G SIM card anymore.

 

[DenniZ]

So, should I leave the 3G SIM card in the 2G phone when I try to upgrade... or take the SIM card out and then try. I don't have the old 2G SIM card anymore.

Your current SIM card from your 3G iPhone should be fine with the 2G iPhone. Just put it into the 2G phone, and activate.