Originally Posted by Optimus5566
i purchased a unlocked HTC one and i use a AT&T gophone sim card. i am not able to get the LTE signals so i would like to know is the phone capable or its an issue.
This happened to me a few months ago. The phone is definitely capable and you will get LTE signals on the $60/month GoPhone plan.
1. First of all, call GoPhone customer support (611 from the phone) and confirm that they have your HTC One whitelisted for LTE. They're going to double check with you your phone's IMEI number (they can already see it, but will ask you for it anyway), and then confirmed that the phone is allowed to get LTE signals. They're also going to double check your APN setting and provide you with the appropriate entries for AT&T.
2. Reboot and see if you now get LTE signals. If you still don't get it, check whether your mobile network settings is set to GSM/WCDMA/LTE Auto instead of GSM/WCDMA Auto or WCDMA Preferred (or maybe something else). If you don't see any LTE option, dial *#*#4636#*#* from your dialer, and in the first drop down box choose 'GSM/WCDMA/LTE Auto' or anything with LTE just to make sure you can catch LTE signals at all. If you were able to find and switch to the setting you want, exit out, and go back to that menu, double checking if the setting sticks. If it does, reboot and try again.
3. Most people will get LTE signals after #1 above, while some were only able to get it after #2. However if you are unlucky like me, the LTE setting does not show up in mobile network and no matter what I do in the hidden menu, the setting won't stick (it's stuck on GSM/WCDMA Auto). I actually tried flashing a different radio at this point (a newer AT&T radio), but still... no LTE for me. What solved this finally for me is that I flashed a custom ROM (in my case it was ARHD 12.2). This enabled me to choose GSM/WCDMA/LTE Auto under mobile network settings, and after that I was able to get LTE. It was great!
Hopefully that helps. Good luck!