i have follow this:
For future reference here is what I did:
In the config_runtime.inc file I...
commented out "%define PATCH_BACK_MS_KEY"
set "%define PB_OPEN_PATH" and "%define OPEN_PATH" to the dashboard of my choice
I compiled the file, named it NKP11_config_open.bin, and put it in the NKP11 folder.
If I understand correctly, NKP11_config_open.bin is only used when the Xbox is powered on using the eject/tray button, so this suits my purpose perfectly.
So i have found config_runtime.inc, edit as write before.
Run make runtime.bat, i have get NK11_config.bin file and rename: NK11_config_open.bin and put it in NK11 folder of xbox.
So i reboot and try...nothing.