I have a SD card reader for Mobile but I don't have a PcYou don't have a PC?
I guess if the sd card fits in the mobile you might be able to get the files you need for sd card on your mobile, I'm not sure.
I have had to add cfw to a few 3DS using mobile. (Note 3, S7 S9) Just need a way to read the SD using mobile.
Just drop the files on the SD and trigger the exploit via 3DS.
But can they format their sd card to Fat32 using mobile? A 3DS will only read a Fat32 sd card.
Googled it someone said they used AParted App on Google Store and was able to format to Fat32.