Bootable system images created by scripts/mkroot.sh:

  LINUX=~/linux CROSS=allnonstop scripts/mkroot.sh

Each system image is built from two packages: toybox and Linux.
Run the ./qemu-*.sh script in the tarball to boot the system
to a shell prompt under qemu. Run the "exit" command to shut down the
virtual system and exit the emulator.

See https://landley.net/toybox/FAQ.html#mkroot for details.