The lock works fine and I've tested it in both positions but it doesn't work.
To be more specific, with defaults settings for Gecko OS, if I turn on SD File Patch and SD cheats, it'll say "Setting up drive.." shortly followed by "SD File Patch Not Found"
If I try with SD cheats turned on, but File Patch off, it finds and applies the codes correctly, but none of the files are replaced (characters/textures/etc)
EDIT: I think I was misunderstanding what the File Patch option was, and that I only need to enable the cheats from the .gct However the File Patch Code still doesn't work. I've tried formatting the SD and creating a single partition of exactly 2GB in size but that didn't work either..
Then make sure to put them in the codes folder on the root of your SD card.
If that doesn't work then just activate the codes in the wii with Cheat Manager.
Put a .txt file with all the codes in it on the txtcodes in the root of your sd card so that the Cheat Manager knows where the txt file is. Make Sure that the first two lines of the txt files says
RSBE01
Super Smash Bros. Brawl
Then go to homebrew channel, use cheat manager, select your txt files with codes in it, and it will tell you which code to enable. Generate it and it will make a gct file and it will put it on the codes folder in your SD, so that Gecko can read it.