lumia 620 Hong Kong in USA: software upgrades

[alwynbilly]

I am interested in other USA residents with the Hong Kong Lumia 602 model. If purchase new, you would have had to reprogram its display to English from Chinese. I have gotten one upgrade, but am waiting for the 8.1 here in the USA. It is unlocked, as when purchased, and I use the AT&T MVNO Airvoice Wireless. I have not succeeded in getting it to work consistently for data (3G) or MMS. It works well and widely for talk and text.
I would be interested to hear from others in a similar state.