I've had a G1 for over 2 years now and want to upgrade. I've rooted the phone with 2.2 and enjoy using the tethering on long car trips. Is there any phone that I can upgrade too that is still on 3G but not phone that T-Mobile recognizes the IMEI? I want to keep my unlimited data plan and 400 text since that's all I need. I've researched that I need a phone that shares the same 3G frequency which excludes AT&T, but if I use a phone T-Mobile recognizes in their database, they'll switch me over to a new plan which costs about double. Any suggestions? TIA
Don't know if you found your answer but:
Buy an unlocked phone outright from someone else besides T-Mobile. Ebay's a good site to find some nice phones cheap, new & used. I just got a new Motorola Razr V3xxrj Titanium for $55. You can use your sim in an unlocked AT&T phone, just at EDGE speeds though. You won't find a phone that carries all the required frequencies for both T-MO (1700mhz,2100mhz) & AT&T's (850mhz,1900mhz) 3G. So probably buy a T-MO phone if you want to use a T-MO sim card AND have 3G.
T-MO won't change your plan unless you ask, or buy a phone that requires a different plan, ie: like a blackberry.
I've been on my G1 Unlimited Data/400 Messages since 2008, on 6 different phones.
I always try to buy unlocked or unlock it myself, be a lot easier to sell if you decide to.