Title pretty much says it all. I have a bunch of retro controllers (NES, SNES, SEGA, etc) all converted to USB and working with their respective games. But this only works when I run RetroPie off the SD card. I recently decided that I wanted to boot RetroPie from a USB stick that I have the ext4 part of the RetroPie image file (/dev/sda1). It boots up fine, but controllers are not detected by the setup script on the first run. The controllers are however detected when it is booting up as I can see them listed before the RetroPie splash screen. I even tried copying the ext4 partition from my working SD card setup to the USB stick with the same result – starts up fine, even launches games but controllers won’t work or even be detected.
I figured it out. I got the ext4 partition from a fresh install of Wheezy on the USB stick and did a fresh install from source. Something about it being set up on the SD card and then transferring it over to USB messes up the USB mappings so controllers are not detected.
Now all I need to do is get my N64 controllers mapped and n64 games working without lag and I will be happy.