broken volume key factory reset

hi every one. i have an htc x one from att. with broken volume key that restarts itself every minute or so. i was wondering if it is possible to use an external keyboard connected to the phone while is on bootloader mode in order to get into recovery mode and factory reset if possible, well boot loader mode says tampered that may means i need to unlock the bootloader and flash back to stock. but without the volume key i cant move in fastboot mode or hboot. bottom line i need and external usb keyboard in order to fix the phone. any help would be very much apriciate

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