Reminds me of how lmsensors bricked some Thinkpads during the I2C probing process. It overwrote some bytes in the "security chip" and wrecked a checksum which prevented the machine from booting. IBMs answer was to replace the mainboard. You could reprogram the chip, but the information was hard, if ever, to get. Some guys offered reprogramming services for a hefty fee.
The main reason was that the security chip, wich was a extended I2C eeprom (24RF02) reacted differently to commands as its non-security counterpart.