andbria1:acsonline:
THat should really have worked. as a last resort you could try the Telstra 2.2 update, since they use 850Mhz too.
http://www.zte.com.au/optus/V9.htm
Flashing with Optus now, then will try again. Also just noticed that the IMEI on the phone is different to the IMEI of the box it came in. I wonder if it got changed when flashing it at some point. This might be a stupid question but: Would the wrong IMEI on the phone stop it from connecting?
this is really a last gasp measure!
Also look at http://android.modaco.com/content-page/337130/zte-v9-light-2-2-update-now-available/page/200/
looks like your IMEI issue is mentioned and also someone has taken a ROM dump of the stock Telecom V9 ROM.
Ive never done a restore from a ROM dump, but that might be the way to go.