Is this T-Mobile device still the best phone to use to tether to the Nokia N810?Is it pretty much plug and play or more difficult?

I purchased that phone (eBay) and was able to tether it with N810. I don't remember having much (if any) problems getting it to work. I tried with my company SIM card (it has data). Even with my own prepaid (T-zones) it does tether and connect, but all you can browse is just the T-zones.

I read somewhere that there is a SW update for that phone, and if updated the tethering capability will be disabled. Therefore I did not update the SW...