constant power "add-tag CP" fails on XO-4?

James Cameron quozl at
Tue Feb 25 22:56:28 EST 2014

The CP tag failure has been fixed and will be included in any new
release of Open Firmware.

It was indeed a bug.

Instead of setting the CP tag in the embedded controller (EC), 128
bytes of invalid data was written instead.

The EC just ignored the invalid data and behaved as if the CP tag
wasn't there.

The bug would only trigger if the EC had not been reprogrammed since
power was applied.  This is why ?sync-ec or deleting and adding the
tag again would fix it. has the technical details.

James Cameron

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