Expansion pack
This is actually REALLY simple!
Only took 2 wires to do it!
Here's the back of the expansion pack (removed the bit of grounding off the edges of the board BTW).
Surveyed what's what and found that the line under the "C6", "C7" and "C8" is in just the right place, and the only points the two contacts under "C7" and "C8" only connect to each other. Below is the line we need to cut. Clearly, the only contact then that needs rewiring apart from the above, is ground.
So, easy to turn the board around and add a dot of flux to the two points as indicated and attach a wire between them - that connects the two pins under the "C7" and "C8" as mentioned.
ie
So, cut through the board with a Dremel to about 80% or so all the way through, not cutting through of course or the traces will get cut.
Folded the board and reconnected the severed ground with a small piece of fairly thick (3 amp) wire.
I know the chip needs a slim heatsink, but this is to show the board done
Proof it works fine:
As you can see, the expansion pack is only around 3mm higher than the height of the expansion pack port itself. This is a safe mod to do as it doesn't need any modification to the N64 motherboard.
Jumper pack
wire three wires (using standard 1 amp wires) as per the pic. No work needed to do to the original port BTW, pop the jumper pack in as normal.
Tested on a few games, works great.
Point is of course that you can have the jumper pack laying lower in your case with this method, without having to remove the port and wire thin wires to the contacts, which can be a good way to kill a board often; this method is safe and easy to do, in comparison.
These pics should show what was done and what the three wires connect to.
This is a simple mod, on reflection, would have been easier if i'd cut more like 90% of the board through, ie until you can see the light through the board cut but obviously not enough to cut through to the other side.
