bu40n often fails to flag errors with ddrescue

[kja70]

I have an Archgon BD drive that sdftool identifies as HL-DT-ST_BD-RE_BU40N_BU10_211705301728_MO4KCTD5208.

I am trying to rescue some of my scratched discs both with Libre and standard firmware. I've noticed that in both cases ddrescue often completes showing 0 errors and 100% success, but there are definitely bad reads since repeating ddrescue multiple times on the same media creates non-matching ISO files.

I believe this is because the drive has some failure mode where it returns junk if it can't read the disc. It would be much better if it returned an error so I would know that ddrescue was not actually successful and could try different techniques like trimming/scraping, more intensive surface cleaning, etc.

Is this just a limitation of the BU40N device? No way to actually have it fail with an error when it actually can't read data?

[thechill]

sound like the insane LG feature named Jamless Play to me.

[kja70]

Yes, I think that’s right. Would be great if there were some way to disable jamless play.