[U-Boot] NAND BBI swap on iMX53

[Luca Ellero]

Hi all,
I've noticed that mxc_nand driver doesn't implement BBI swap for reading 
factory marked bad blocks on NAND devices, as suggested by Freescale:

https://community.freescale.com/servlet/JiveServlet/download/329191-260869/AN_MX_NAND_BAD_BLOCK.pdf

BBI swap is implemented in Freescale iMX53 BSP (which use an old u-boot 
version 2009.08) but not DENX official U-Boot.
Isn't this a dangerous behaviour? As far as as I can see it can lead to 
an irreparable loss of factory bad blocks markers.
Can someone please give me some information about this topic.
Thanks

Best regards
Luca Ellero