Lunar Knights

The fourth game in the Boktai action-RPG series by Kojima Productions. This one was released as a different IP outside Japan, since the first two Boktai games were not as successful abroad as they were in sunny Japan and the third one was skipped completely. Unlike the original GBA trilogy, this DS version did not include a built-in solar sensor (you had to plug in one of the previous Boktai games into the DS's GBA slot if you wanted to use one).

Mega Man Star Force Left-overs
The Japanese game has an option for an optional cross-over sidequest, by linking this game via Wi-Fi with the Japanese version of Mega Man Star Force. To start it, you have to enter a modified version of the Konami Code (only with LRLR after the D-Pad input) when at the eastern Solar Bank.

While this sidequest has been dummied out from all other versions, quite a bit of it survived the process, and can be accessed with Action Replay codes. The ones listed here work for the US version.

Unused Terrenial
War-Rock (Omega-Xis) was the Terrenial you got as a reward for this sidequest. It seems his Trance state doesn't work anymore, and you have to choose him from the subscreen if you want him to be visible. Djanjo (Aaron) 221ec044 0000001d 221ec045 00000000 Sabata (Lucian) 221ec054 0000001d 221ec055 00000000

Unused Items
The badges you get from this mission are still coded. Luna Emblem still works as intended, but the Sol and Dark Badges are a bit glitchy. 221ec32e 00000073 221ec32f 00000000

221ec330 00000074 221ec331 00000000

221ec332 00000075 221ec333 00000000

The items specific to this sidequest (Biometrics W, Christmas Cake, Otoshidama and Valentine's Chocolate). This code overwrites the last four slots in your inventory, so make sure they are empty. Some items, like the Brother Band and Geo Glasses were seemingly completely removed. 221ec078 00000050 221ec079 00000000

221ec07a 00000051 221ec07b 00000000

221ec07c 00000052 221ec07d 00000000

221ec07e 00000053 221ec07e 00000000

The cross-over equipment specific to this sidequest (Pegasus Rock Head, Dragon Rock Body and Leo Rock Leg). This code overwrites the last three slots in your inventory, so make sure they are empty. 221ec66a 00000010 221ec66b 00000000

221ec66c 00000021 221ec66d 00000000

221ec66e 00000032 221ec66f 00000000