[Reset Button] On Controller

[Gillbert]

It's not so easy, it's 6 of 10 difficulty level.

You have to use the "sense" wire on the controller (green wire, originally grounded), isolate it from the ground on both controller PCB and from Dreamcast controller board, and then use that wire to a switch placed at controller. The sysreset is done by grounding the pin 2 of IC201 (TP206 of Holly chip).
The hardest part of the mod is isolate the sense pin from the ground of the DC controller board, because it's a double side PCB and you need to remove the male controller plug for cutting the trace.

I'll you provide some photos in the weekend.