i think one file is missing "AutoRun.exe"
i found this:
Here's how to make your next ROM UC capable:
- Cook the attached SDAutoRun.exe into \windows
- if AutoRun.exe isn't already in \windows then place a copy there too. Note: some devices don't have a compatible AutoRun.exe. If you have issues, try the attached version.
- Replace the "RST: Reset" line in config.txt with "EXEC:\windows\SDAutoRun.exe"