EDIT2: A new solution (much more invovled ) was suggested by Charles MacDonald this will be interresting to try.
EDIT: Nice, I got my answers in that thread. I'll have to backtrack on when did this become a dangerous thing to try, FYIW I used 10k res to short pin 34.
This MOD does not work on my SMS:
I tried everything, including burning a Japanese BIOS which works great here:
While its cute and all (especially with my RGB mod to a Commodore 1084), I still don't get the mark III boot on my Wonderboy 1/2/3 carts when I ground pin 34 on 315-5216.
Another user is getting the exact same prob with this motherboard rev.