Upgraded to v64i, as others have experienced, I have no 3g connection (simply says "No Service" at the top with it enabled), but also more frustratingly, I cannot get Push Email or any form of web browsing / internet to work either.

I downgraded back to a much earlier version, and the 2G connection is back working for the internet again. (Still no Push email though, and when I do get the email / calendar etc to work it won't 'Push' the mail in, I have to manually connect for it to refresh (and yes, I’ve checked, re-checked and triple checked all settings…)

Most annoying!