Does the following part of the help text add any value: "Note: This option will increase the size of the coreboot image."
I would think that it would be obvious that additional debug functionality makes the coreboot image bigger. Could you just strip that from the help text?
Also, posting patches in the body of your messages might make it easier for reviewers to comment on specific lines. Would it be possible for you to do so in the future for smaller patches like this one?
Thanks, wt