Since the encryption used is AES-128-CTR, there's a static XOR pad (generated from the key) applied when encrypting/decrypting. It repeats each 0x40 (what a fuck-up, Nintendo). Here's the XOR pad used for the *.lst file (hexadecimal):
00: F7 4C 6A 3A FB 82 A6 37 6E 11 38 CF A0 DD 85 C0 10: C7 9B C4 D8 DD 28 8A 87 53 20 EE E0 0B BE B4 3A 20: 0D B5 5F 75 36 37 EB 35 6A 34 7F B5 0F 99 F7 EF 30: 43 25 CE A0 29 46 D9 D4 4D BB XX XX XX XX XX XX