it's not just that. Reading scratched blocks means sometimes it might work, sometimes it might not. lets say 1% of the time you get a good read. If the ECC b

it's not just that. Reading scratched blocks means sometimes it might work, sometimes it might not. lets say 1% of the time you get a good read. If the ECC block is 16k and you always read in 16k blocks, if you get that 1% magic time that the read succeeds, you got the whole block. If however, you read 2k blocks, you need to have the same luck 8x times. From experience of recovering bad DVDs and BRs, there were discs I had to pass through 100+ times to get a valid read on all blocks. This is also because, the underlying hardware will always do a full ecc block read (only way for it to determine that it read the block correctly, to read whole block and verify it), so any smaller reads are pointless.