Quick energy efficient reboot from ultra-low power mode for a system on a chip

A system, comprising:

• a volatile memory;
• a power controller configured to control power to multiple power rails;
• a boot loader configured to perform a cold boot by loading one or more binary images from a non-volatile memory into the volatile memory, and authenticating the one or more binary images;
• and
• a sleep state controller configured to place the system in a sleep state by placing the volatile memory in a self-refresh mode, wherein the volatile memory stores the one or more binary images in the self-refresh mode and the one or more binary images include variables, and outputting a sleep-state enter signal to the power controller, wherein the power controller is further configured to collapse the multiple power supply rails in response to the sleep-state enter signal, to power the volatile memory in the sleep state, and to restore power to the multiple power supply rails in response to a wakeup event;
• wherein the boot loader is further configured to take the system out of the sleep state by taking the volatile memory out of the self-refresh mode when the power to the multiple power supply rails is restored, initializing the variables, and causing one or more sub-systems to run the one or more binary images on the volatile memory;
• and
• wherein the boot loader is configured to skip authenticating the one or more binary images when the system exits the sleep state.