Thank you for your reply
TurdPooCharger!!
Unfortunately, I didn't have any luck with that method either (I actually tried it first, before restorting to TWighLightMenu...)
I followed the method given by dpad to the letter really (or so I believe anyway): I took DSiWare games NDS files (from a certain collection folder on "that ISO site"), I extracted some of these to a folder along with "make_cia.exe", and then in a command line I typed:
make_cia --srl=WHATEVERGAMENAME.nds
which successfully outputs a .cia alright.
Although once I put it on my SD_Card and try to install it, FBI refuses and gives me an error screen with some codes (I could quote these if it helps?). I use a New 3DSXL under Luma3DS, by the way.
Do you see what I'm doing wrong here, or what I could try to make it all work?
Any help would be more than greatly appreciated, as you can guess!!! I have like a thousand NDS DSiWare, yet at the moment no way of playing them on my 3DS... :-/