GNU Boot also builds some debug images that are shipped in separate
debug archives (like gnuboot-0.1-rc3_x200_8mb_debug.tar.xz).

The debug images have the following differences with the regular
images:

- The serial port is enabled, its speed is set to 115200, and the
  Coreboot debug level is set to 7. It's possible to bring it up to 8
  without recompiling the image by modifying the cmos.default file
  inside the image. In addition POST codes are also printed on the
  serial port.

- When the computer has a Coreboot build setting for that (all
  computers but QEMU have that), memory debugging is enabled. This can
  help diagnose RAM compatibility issues to potentially fix them in
  Coreboot.