Computer system and method for replacing obsolete or corrupt boot code contained within reprogrammable memory with new boot code supplied from an external source through a data port

摘要

In accordance with the invention, a computer system is provided with a flash read-only-memory (ROM), a microcontroller and a data port. The microcontroller initially owns the flash ROM. The microcontroller further has a separate ROM upon which it can execute boot- up instructions. After booting up, the microcontroller checks the flash ROM contents, preferably by performing a check-sum of the flash ROM contents. If the checksum of the flash ROM contents matches an expected value, the microcontroller releases ownership of the flash ROM to the computer system so that the computer system boots-up as normal. If the microcontroller determines that the flash ROM has become corrupted, the microcontroller accesses the data port and looks for a flash programming protocol. If the protocol is present at the data port, the microcontroller receives the data from the data port and programs the flash ROM accordingly. In this manner, the flash ROM can be updated to a good known state, even if the computer system is not able to boot up due to, among other things, the corruption of the flash ROM.