step s 302 if the os 1 has not been removed then the method proceeds to step s 303 in step s 303 the processor 15 determines through the content of the boot loader 13 or the result of the user operating the device peripheral interface 11 whether to load the os 1 or not if the os 1 of the processor 15 determines to load the os 1 then the method proceeds to step s 304 otherwise the processor 15 performs the boot loader 13 to load the os 2 step s 302 in step s 304 the processor 15 checks whether the authorization of the os 1 is overdue or not if the authorization of the os 1 is overdue then the method proceeds to step s 306 otherwise the processor 15 performs the boot loader 13 to load the os 1 step s 305 in step s 306 the processor 15 removes the os 1 and restarts the electronic device 10 then the processor 15 determines whether to release the system resource i e usage space of the os 1 or not if the processor 15 determines to release the system resource of the os 1 then the method proceeds to step s 307 otherwise the method proceeds to step s 308 in step s 307 the processor 15 burns a merge instruction into the eeprom 12 such that the processor 15 will release the system resource of the os 1 i e the first usage space for the os 2 at the next startup then the processor 15 restarts the electronic device 10 and the method proceeds to step s 302 in step s 308 the processor 15 restarts the electronic.