Need help to find US firmware and rom to use LTE

Hello everyone,

I hope someone can help me.

I have an asian unlocked M8 and I live in Mexico so I cant use LTE. To solve this I got S-off, supercid, wwe mid and wwe firmware with Android Revolution Rom and still cant use LTE (Europe LTE bands do not include band 4 aws, so its the same crap). I tried to flash att and t-moble radio but mi phone did not recognise the radio file (Unknown baseband) so I get no signal. Then I flashed the wwe radio and got the same no recognition problem. The only way to get back signal is to flash again the firmware (it does not work to switch the att radio image in wwe firmware)

I need att or t-mobile bands to use mexican carriers Telcel or Movistar LTE (band 4 aws) and I guess I should use att or t-mobile firmware with the matching based rom.

- Can someone recomend me a rom version and firmware version to download??
- Is the unknown baseband problem because of the wwe mid? Should I also change the wwe to att or t-mobile mid and cid??

Thanks for your time and help!!