I have a pi1 a+ and have built a handheld game emulator running emulation station. I had the system working well, until I set the overclock to turbo. I was trying to get mario kart 64 to run. It would start, then just go to a black screen. Well, anyhow, now when I boot the system, raspian loads and the screen is fine, but when the retro pi splash screen comes up, it freezes and shakes. Is there a way to avoid the retropi from starting, and go right to retropi config? Is there a keyboard process for this?