From a Micron spec sheet:

1 page = 4,096K
1 block – 1 MiB
1 LUN = 4,096 MiB
Min number of valid blocks per LUN = 3,996
Difference between max and minimum = 100 blocks or 100 MiB

An invalid block is one that contains at least one page that has more bad bits than can be corrected by the minimum required ECC.


If a sector = one page (4k) 40,960 pages (sectors) = 40MiB.

Even is all bad sectors were on one LUN (unlikely) the LUN would still be operating within acceptable parameters.