Help t mobile g1 wont update stuck on 1.0

[g1user7]

please help i just purchased a t mobile g1 of ebay and i cant update it. it is stuck on android 1.0 and even though internet is working fine i am not recieving any update notifications I have tried flashing it but it wont work i really want to get it to 1.6 what should i do? ps i am a new user