SIMtrace phone-side VCC

Hi folks, Seems not all phones use 3V signaling if the PHONE-side VCC pin is tied to 3V. This one insists on 1.8V : BLU SAMBA JR PLUS Is this trick of tying VCC to 3V standard behavior? For future version of the board, it might be interesting to tie the VCC pin to an ADC input, to detect different voltage levels so the firmware can wait until phone decides to use 3V. Cheers Tom