20 Most Recent HTC One M8 32 GB Grey Smartphone - AT&T 2 GB RAM, 32 GB Internal Storage, Android, 4G, 5 MP Camera - Page 9 Questions & Answers

Unlock the Bootloader through HTC first they will walk your through it FREE of charge then go to https://forum.xda-developers.com/ For further instruction to ROOT and unlock the Sim card slot

You can definitely unlock and this phone. Sign up for a free account with HTC and UNLOCK the BOOTLOADER first then you can root it and then unlock the SIM card Slot also Look on XDA Developers site for full instructions. Here is a link to the instructions. OK https://forum.xda-developers.com/ This is what I got when I tried to post the link to your actual phone (The word desrie is considered as profanity on Fixya. Please review your answer and try again.)

First switch on bluetooth (settings---bluetooth).
Start > Settings > Communications and Add new Bluetooth headset. htc will search bluetooth headsets and find it. it will ask you to enter bluetooth passcode, usually it is 0000. then finished and you have paired Bluetooth headset with HTC

Here you go! http://dl4.htc.com/web_materials/Manual/HTC_One_A9/NA/HTC_One_A9_US_User_Guide.pdf?_ga=1.38498275.178127690.1484142472 http://www.htc.com/us/support/htc-one-a9/

Sorry, Take it to your carrier they should be able to help