i.MX6DQ RM of sect 18.104.22.168 NAND Flash Boot Flow and Boot Control Blocks (BCB) description.
Driver reads raw 2112 bytes of first sector and runs through software ECC engine that determines whether FCB data is valid or not.
In Figure 8-5. FCB Search Flow, it has become Read 4K, and ReadCount ++.
Would you please more detail information.