Marks whether this bootrom-update entry represents the effective bootrom (main(1)) or a non-effective one (none(2)); it must be set to main(1) to initiate an update, and any previous main(1) entry for the same physical index automatically becomes none(2) if the update succeeds, or the object reverts to none(2) if the update fails. An admin tracking which bootrom entries actually took effect after multiple update attempts would check this field alongside hpnicfSysBtmErrorStatus.