(As far as I know, maybe I am wrong) A9LH is only installable in 9.0 - 9.2. In 2.1 there was no "Arm9loader", which was added in 9.0, and in newer versions(>=9.3) the Arm9 permissions were patched, but if installed A9LH in 9.0 - 9.2 and keeped(no overwriting Firm0 and Firm1), it worked on newer...