futility: gbb: Read only the GBB region from flash

BUG=b:265861606
BRANCH=None
TEST=futility gbb --get --flash --flags --hwid --digest --rootkey=/tmp/rootkey --bmpfv=/tmp/bmpfv --recoverykey=/tmp/recoverykey
TEST=futility gbb --get --flags --hwid --digest --rootkey=/tmp/rootkey2 --bmpfv=/tmp/bmpfv2 --recoverykey=/tmp/recoverykey2 /tmp/bios
TEST=diff the above
TEST=confirm that it is quicker (3s vs 26s on one dut)

Change-Id: I398e40a1cc50a6921e0385277fc03d0b7fa7c9b8
Signed-off-by: Evan Benn <evanbenn@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/4170147
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
Tested-by: Edward O'Callaghan <quasisec@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
1 file changed