How do I enable a simcard on my HTC One M7?

A

AC Question

I'm running the 7.21.980.35 version of the operating system, and can't find instructions anywhere regarding the process for enabling the use of a simcard on my device. I can boot the phone, see the home screen and menu, as well as connect to a wifi signal, but the mobile won't register any simcard I insert.

I'm also wondering if anyone has a link to the stock firmware for the above operating system. The phone is second-hand, and when I boot to the bootloader it says the device has been tampered with. I'm hoping flashing the firmware to the original kernel version will help with my first query.

Any reponse would be much appreciated.

Regards,
Sam.