To set up build environment:
Executables for cross-compiling are stored in:
If the Gumstix won't boot, you can (rather slowly) flash the filesystem over serial.
If the gumstix will boot, then flashing from RAM disk over ssh is faster, but if the process fails or gets interrupted you'll have to fall back on the serial method. Remounting the filesystem read-only may not work, and the whole processed failed. Reflash over ssh