Play Coin Setter 3DS
3DSx Play Coin Setter is a homebrew that allows Ninjhax users to modify the 3DS's play coin counter, in other words providing infinite play coins.
This code is a modification of yellows8's 3DS HomeMenu extdata Tool, which contains within it code to modify arbitrary 3ds extdata.
Available in 3DSX/SMDH format.
Copy both playcoin.3dsx and playcoin.smdh to sd:/3ds/playcoin/, then run it with the Homebrew Launcher.
Choose the number of coins you want from the list, then exit using B. No more than 300 coins can be held at a time, this is a system limit.
An option is also available to backup and restore the decrypted gamecoin.dat to the SD card, however this is not likely to be useful to anybody.