Android 1.6 is the last OFFICIAL update. Some people have taken the G1 up to 2.2 through custom ROMs. You can check XDA-Developers for more info on custom ROMs and on flashing them. If you are willing to go the custom ROM route, read, read and read carefully and follow the instructions. Flashing is not for the faint of heart though it isn't a traumatic experience, as long as you have the necessary knowledge.
Just signed up today and would like some suggestions.
Got a HTC T-Mobile G1 running 1.6 firmware; want to update firmware but phone says it is up to date. Saw websites about 'rooting' the phone but I don't have a PC(windows) I got a Mac.
Looking for someone/someplace to do this for me. Anyone know who I could possibly send my phone to OR any other suggestions to update this phone without buying a new/different one?
Thanks for any help you can give!
My first suggestion is always to start at CyanogenMod.com There is a wiki specifically for rooting the G1, installing an appropriate SPL, Recovery and then of course CyanogenMod 5 (android 2.1) or CyanogenMod 6 (android 2.2). The wiki is at http://wiki.cyanogenmod.com/wiki/HTC_Dream (The dream was the release name for the G1) Also, visit the cyanogenmod forums for the G1, link on the left, lots of info there as well.
Second, visit Modaco, at http://android.modaco.com/index There is also a lot of info on the forums and you can ask questions, etc. There is even a forum board for complete beginners.
For what it's worth, CyanogenMod 6 was a fantastic rom on the G1, That would have been my preference if you decide to root/rom. Since you are new to this, my suggestion is to do some reading so you are familiar with what it is you will be doing.