The North American 4G bands will not be officially supported but in fact they will be accessible, you can connect to any 4G networks in the USA using a UMIDIGI S2 Pro. But I repeat, it is not an official statement, UMIDIGI is not responsible for any connection or stability issue on 4G networks in the USA.
wifi always on issue solved by myself,,go to settings ,,type in search box,,scanning...it will show you wifi scan always on option.. turn that off...viola...
ended up rooting my phone for no reason )
According to the website, the S2 Pro still does not have all of the LTE bands for the US market. B1, B3,B7 and B20 are on the spec sheet. So disappointing.