Importance

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Abstract

A system and method for performing software patches for embedded system devices in which the firmware of the system is included in non-alterable storage of the device. The patch mechanism provides a means for finding firmware errors, prototyping fixes to the errors and/or prototyping new functionality of the firmware of the embedded system. The system comprises an embedded system device coupled to an external memory. The device includes a non-alterable memory, including firmware, coupled to a processor. The device further includes a relatively small amount of patch RAM within the device also coupled to the processor. The patches are loaded from the external memory into the patch RAM. The device further includes a means for determining if one or more patches are to be applied. If the device detects a patch to be applied, the system loads the patch from the external memory into the patch RAM. The device also includes a breakpoint register. When the value of the program counter of the processor equals the value in the breakpoint register, a patch insertion occurs, i.e., the processor deviates from executing firmware to executing patch instructions. Preferably, the embedded system device comprises a single integrated circuit. The processor may include a plurality of breakpoint registers. The patch may be encrypted for increased security. Multiple patches may be chained together, and run-time patch replacement is contemplated.

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First Claim