Do u mean the wireless 3ds to pc thing from the settings? I'm pretty sure that was only n3ds because of the nasty SD card location. Idk bout cfw though
There is a patched version around the internet (can't link here) that work on non-New models. I have it on my o3ds and it work perfectly, so it should work also on your 2ds
it should work and quite useful to transfer small files (ncchinfo.bin to generate xorpads, screenshots from ntr to be uploaded), for bigger file, just remove your sdcard.