cgptlib: Add support for IGNOREME GPT signature

This patch makes cgpt aware of a special "IGNOREME" GPT header signature
string that may appear in either the primary or the secondary GPT and
cause cgpt (and other cgptlib clients) to completely ignore that GPT. It
will continue to function correctly for all other purposes (using the
data from the non-ignored GPT), but never write any data back to the
ignored GPT.

TEST=unit tests

Change-Id: I7e53542385ae9d8d24dc25b75e91f4ff4917f66f
Signed-off-by: Julius Werner <>
Reviewed-by: Nam Nguyen <>
(cherry picked from commit 39910d062dffcd16683e0626dac1e7064991c7e5)
Reviewed-by: Bernie Thompson <>
Commit-Queue: Bernie Thompson <>
Tested-by: Bernie Thompson <>
7 files changed