So the flashcarts in question are a Supercard DSTWO and an R4i Gold RTS 3DS, both of which are working flawlessly on my New 3DS on 11.2.0-35U. However, the R4i was intended to be used on an Old 3ds that was running 9.24 but the system would not "read" the cart. The cart would not be recognized as being inserted in the main menu, original 3ds cartridges work ,but the flashcarts just don't show up. I tried looking for some more info on the issue but I am stuck now. Any ideas on what could be the root of the issue or how to fix it? PS. I am not the original owner of the Old 3ds, it belongs to a young nephew so it is quite possible it has seen some abuse. UPDATE: Just found and tested (on my personal 3ds) an official and working copy of mario kart ds. It seems the Old 3ds is refusing to read any cartridges with the ds form factor.