Starting standby system and method with a single internal memory

It is a kind of start backup system and method that with the single memory. It can be connected with CPU and realizes manual start backup on single memory. The system comprises a flash and an address mapping circuit. The flash stores the initial start code and backup start code, and records the storing address of initial start code and backup start code in the first address and the second address. The address mapping circuit comprises an inverter, a selector, a logic gate and a switch. The method comprises the following steps: (a) power on; (b) judging the output mode of switch; (c) if the output mode is on, the CPU activates the initial start code in flash; if the output mode is off, the CPU activates the backup start code in flash; (d) startup.