the pockettv team

you can use KernelIoControl(IOCTL_HAL_GET_DEVICEID,...) but this requires
the application to be trusted - this is one of the privileged APIs.

you can also access another unique ID used by the phone API, but it also
requires the application to be trusted.

AFAIK there is no way to obtain an unique IDentifier (on a Smartphone)
unless your app is trusted (i.e. you need to be signed by the special
certificate that gives you access to the privileged API's.