We're already having a very nerdy, hands-on day here so we might as well continue. The original Xbox contained a readable/writable TSOP chip which means that in order to "mod" the system you didn't even need to install a modchip. Just flash BIOS code directly to the TSOP. What's the point? You don't care about the original Xbox? Here it is then:
The Xbox 360 has a TSOP chip as well.
Smarter people than I will determine if this can be exploited. The Soft Life writes, "Does the existence of a TSOP on the Xbox360's motherboard mean the same LDT security attack will be available? Probably not. But it seems to at least be an potential opening.