This is based on the falcon jtag exploit, and instead of the resistors, we are using two diodes (I have been told that 1n914 switching diodes work for this). This is supposed to be a better method than the 3x330 ohm resistors method.
the original quote from the xboxhacker thread
While I agree that the resistors arent the optimum solution, the current >xenon wiring is indeed very safe. (It doesn't use resistors at all). In fact the 2 signals that you are concerned about are already "pulled up" to Vgpu and the SMC can only pull them low for jtag. There is no possibility of overdrive whatsoever, and those parts can be left in with no harm.
To that end, xenon users should also implement the new level shifting scheme too, as it is electrically superior, and uses less parts.
For xenon use:
j2d2.7---------j2d2.4 (jumper wire)
and my diagram:
and an alternate diagram using actual images of diodes instead of symbols: http://imgur.com/ptWYM.png
the source image is from: http://www.xbox-scene.com/tutorials-xbox360/blaster360.php
So, I will be rewiring my box with this method when my new 30 awg wire arrives in the mail. If I have made an error in the diagram, please let me know so that I may fix it!