[U-Boot] U-boot bad block table

[Rumsey, Carl A. (GSFC-408.0)[SGT INC]]

I have recently been working with u-boot v2016.07 for microblaze architecture and have a couple questions regarding the bad block table generation for a nand flash system. Please note our system is functioning correctly and this post is more to determine exactly what is happening during u-boots scan of the OOB region. We have run multiple pieces of software to determine the bad blocks within our 32GB (8x4GB) nand flash. U-boot catches all of the known bad blocks plus we are finding extras as shown below. Note in below example device 0 had 0 bad blocks.  Im assuming the bad blocks it did report are simply reserved. My question is other than storing the bad block table what more do we reserve blocks for with u-boot?

Device 0 bad blocks:
  1ff80000
  1ffa0000
  1ffc0000
  1ffe0000
  3ff80000
  3ffa0000
  3ffc0000
  3ffe0000
  5ff80000
  5ffa0000
  5ffc0000
  5ffe0000
  7ff80000
  7ffa0000
  7ffc0000
  7ffe0000
  9ff80000
  9ffa0000
  9ffc0000
  9ffe0000
  bff80000
  bffa0000
  bffc0000
  bffe0000
  dff80000
  dffa0000
  dffc0000
  dffe0000
  fff80000
  fffa0000
  fffc0000
  fffe0000


Regards,
Carl Rumsey