Get decrypt9 from its github (
https://github.com/d0k3/Decrypt9WIP/releases)
extract the zip and take Decrypt9WIP.bin and copy it to your sdcard:\aurei\payloads folder. Then rename it to "default.bin" or whichever combo you want.
If you named it default.bin you can boot decrypt9 by holding L+R
Other combos are x.bin, y.bin, select.bin, start.bin, right.bin, left.bin, up.bin, down.bin,
and you only need to hold L + combo to boot (Like L+X or L+Y) (b.bin support was removed in 4.1)