It's not just related to jtag. If it's a "standard" ROD, just the clamp replacement will not change anything. You also have to reflow it.
but the thing is all the pads you connect a cygnos chip to have bits of solder on them and you know by looking at it that there has been something soldered to it and been removed.
most of the X360's i seen and have, the holes are filled with solder stock........
now if you see it's really dull or lumped out ,then someone has been in there...
but it still don't confirm you end result.. you did read Arakon's post right....