You did unnecessary things, if you're playing latest public 0.5.0.3.1, then all cheat codes work
Why do you get "invalid code" then? Simply because you mistyped it, either wrong spelling or you added an extra whitespace either to the front or the back of the word, Android likes to add trailing whitespace s to words so next time just check if the code is for example "SLOTH" and not "SLOTH "