Gprs Shield with Mega 2560 -- power problem

I have problems with version 2.0 of the gprs shield, I think the 5v of USB Arduino that fuel is not sufficient to feed even the modem :open_mouth: :open_mouth: … with version 1.0 I’ve never had problems but now with the new modem powered by arduino too many strange things happen.
Plus, if I feed arduino with only the USB drive into your computer’s modem goes off … :confused:

how come you chose to power through arduino if this does not make it?? :imp: