I'm using a Samsung Galaxy S5-G900I (the Asia-Pacific version) bought in Taiwan to access the Wind network in Italy. The phone can use the 3g network in Taiwan, but in Italy it can't establish a connection (the error message is slightly different then with no connection at all, but it still doesn't download anything).
These are the informations I found about the S5 and carriers' frequency bands: in Italy and in Taiwan. The Italian operator uses both the 900 and 2100 frequencies for the 3g, while the Taiwan operator only uses the 2100 one.
As I understand, since the Taiwanese phone isn't accessing the internet the Italian operator is using the 900Mhz frequency band. The phone should be able to receive on that band, but it's not, is there a way I can set the S5-G900I's 3g to use the 900Mhz frequency (Band 8 in Italy)?
According to this answer the only way is to flash a (unspecified) hybrid modem, isn't there a method campatible with the current installation of Android?