dunno if this is entirely relevant but i once had a DS Lite that was OK playing retail games, everything worked, except it would never pick up my action replay
my other DS Lite detected it just fine as well as retail games
so it might not be the contacts of your card, could be the 3DS. have you tried it on another system? If it ends up working then you just wanna swap out the game cart slot on your 3DS which is actually pretty easy to do
actually this card I'm trying is from a friends, because don't worked in his system he asked me to try on mine :x
You should try this fix https://gbatemp.net/threads/no-gateway-3ds-card-found.378077/#post-5269020.
looks similar but here the diagnosis do not worked like his one, I'm not taking off the label because we will try to replace it with the reseller








