Theory Question: Does crypto-erase also delete the Backup MBR (Master Boot Record)?
Answer: No, it only zeroes out the SDSpace. The MBR is not touched.
For software-encrypted Hard Disk Drives (HDDs), crypto-erase will wipe SDSpace, which contains the protected DEK (Disk Encryption Key).
The MBR (including backup MBR) is not touched.
See Article # 447 as well, the two questions were asked at the same time and may be associated.
Note: This info provided by Tony Kou - questions for further details should go to him, then the question and the answer should be added to the KB.