Pretty sure it didn't had an accessible SD card "Revolution Pi has a specially adapted Raspbian operating system, which is equipped with a real-time patch. The use of Raspbian ensures that most of the applications developed for the Raspberry Pi can also be used on the Revolution Pi."
The Raspberry Pi Compute Module built into the Revolution Pi products has an eMMC of 4, 8, 16 or 32 GByte. Each product has a micro USB receptacle via which it can be flashed or mounted from an attached computer. Users are free to use whatever image they want.