[Q] Optimizing modem for i317 on T-mobile network
I bought a used ATT I317 for use on T-mobile network. Just got everything set up, had to flash the J2 modem in order to work around the unlock. Without any further tinkering, it looks like I am getting access to the 4G network via notification (no indication of access to LTE) but getting highest speeds of about 10.25 Mbps down 2.5 up, and lower speeds of 3 Mbps down. I'm wondering if an updated ATT modem would remedy this problem or if I should get a T-mobile based ROM and flash the updated T889 modem to it?
Many of the posts I have come across are older and I believe before the tower integration. Not sure if it is necessary to go further in modem modification or do the AWS band work around. I have my phone rooted and plan to try out different ROMs, especially cyanogen and DittoNote 3, would it work better for me to access the T889 bands from variants of those, or other ROMs?