Okay,... my turn to ask for help!

I've got a v1.3 xbox that I've installed an Aladdin Advance v32 chip into. I've installed hundreds of these before, but this is the first time I've come across this problem.
I've installed the chip via headers and ground D0 (no BT, L1 & L2). When the machine is turned on (either by the power button or the eject button), it will sort of frag - the machine powers up and the LED goes green, then the machine turns off for half a sec and then back on and boots normally. My biggest concern is that every time it 'frags' it resets the clock.
I've quadruple-checked my LPC connections - even going as far as tearing out the header, making sure everything was clean, and then re-installing. I've also tried another modchip - same thing. I've tried flashing a different bios onto the chip - still the same thing (I'm using X24981.06 BTW).
Now the machine won't 'frag' when the D0 is disconnected from GND, so it would leave me to believe that it has to be some sort of problem with the LPC connections. It's just really strange that it 'frags' once, then boots up just fine (it doesn't frag three times like you would normally expect from a bad LPC connection). Also, if I can flash the modchip (via XFlash), then I would think that the LPC connections must be fine (I flashed the chip 3 times without any problems).
I'm at a bit of a loss here, as I've tried everything I can think of. Can anyone suggest something? TIA