ddrescue shows 0 errors/100% rescued on Libre-enabled drive, but makemkv fails with hashcheck errors

Discussion of LibreDrive mode, compatible drives and firmwares
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kja70
Posts: 14
Joined: Mon Jun 15, 2020 7:40 pm

ddrescue shows 0 errors/100% rescued on Libre-enabled drive, but makemkv fails with hashcheck errors

Post by kja70 »

I have a BD-RE HL-DT-ST BD-RE BU40N flashed with Libre firmware 1.04 (21200506).

I own a slightly scratched BD that I am trying to backup with the method recommended here — first use makemkvcon to “bless” the disc, then ddrescue -b2048 to make an ISO copy. ddrescue completes with 0 errors, and reports 100% rescued (sometimes with a few initial read errors that are fixed on retry). But the resulting ISO file still reports hashcheck errors when I try to back it up with makemkv (whether by pointing makemkv directly at the ISO, or mounting the ISO via loop back and pointing makemkv at a copy of the mounted directory along with a copy discattd.dat that makemkv generated earlier.

The hashcheck errors start about 15% of the way in and then the backup fails.

Same result using mplayer or bluray_copy pointed at the same ISO file.

Any idea to troubleshoot? Is there some way a 100% successful ddrescue could still be saving bad data off the disc?

I just noticed that after using ddrescue three times to generate an ISO on this same disc, with 100% success each time, the three different ISO files have different md5sums. So clearly something is going on where ddrescue is not returning the same data each time notwithstanding finding no errors.

Example errors on processing:

Code: Select all

The source file '/BDMV/STREAM/00010.m2ts' is corrupt or invalid at offset 1187463168, attempting to work around
DEBUG: Code 179 at %-Nz)AJ{%l]mS>+:6G!g:213133250
DEBUG: Code 0 at <|8L(k"IL<"*sQUDi1;f:213131157
DEBUG: Code 0 at <|8L(k"IL<"*sQUDi1;f:213131272
DEBUG: Code 579816 at <|8L(k"IL<"*sQUDi1;f:121261773
DEBUG: Code 0 at "<}&y)/QPll3W.ITZ7Y<&:213129984
DEBUG: Code 0 at b3O_v@D+A?$gJfkWPc.et:213137068
DEBUG: Code 1 at 1WA)q~a}1=@~!1!@:213132537
DEBUG: Code 0 at b3O_v@D+A?$gJfkWPc.et:213137068
DEBUG: Code 0 at b3O_v@D+A?$gJfkWPc.et:213137068
LIBMKV_TRACE: Exception: Error while reading input
The source file '/BDMV/STREAM/00010.m2ts' is corrupt or invalid at offset 1190547456, attempting to work around
The source file '/BDMV/STREAM/00010.m2ts' is corrupt or invalid at offset 1187463168, attempting to work around
kja70
Posts: 14
Joined: Mon Jun 15, 2020 7:40 pm

Re: ddrescue shows 0 errors/100% rescued on Libre-enabled drive, but makemkv fails with hashcheck errors

Post by kja70 »

Further update--I've now run ddrescue six times, some without "blessing" the disc first, some after. Each time results in a file with a different md5sum, despite the fact that ddrescue reports 100% rescued. Could this be a Libre firmware issue? Should I try to restore the original firmware?
thetoad
Posts: 140
Joined: Thu Jul 28, 2016 4:18 am

Re: ddrescue shows 0 errors/100% rescued on Libre-enabled drive, but makemkv fails with hashcheck errors

Post by thetoad »

might be a bad memory issue. its also possible that libedrive itself mucks with the content. experiment with a disc that makemkv doesn't complain about and see if the same thing happens (i.e. that you get diffrent checksums each time)
kja70
Posts: 14
Joined: Mon Jun 15, 2020 7:40 pm

Re: ddrescue shows 0 errors/100% rescued on Libre-enabled drive, but makemkv fails with hashcheck errors

Post by kja70 »

thetoad wrote:
Thu Jun 03, 2021 8:44 am
might be a bad memory issue. its also possible that libedrive itself mucks with the content. experiment with a disc that makemkv doesn't complain about and see if the same thing happens (i.e. that you get diffrent checksums each time)
I have processed several other BD discs (using both MakeMKV and ddrescue as needed) without this problem on the same drive with the same Libre firmware release. Can someone point me to instructions for re-imaging the firmware that came with the drive? I have a tar file I created using sdftool dump before imaging Libre, but it's not clear to me what steps I take to restore those files to the drive. The tar file contains:

Code: Select all

fd_fwdate.bin
fd_sn.bin
inq.bin
rom_003000.bin
rom_1EC000.bin
rom_1F0000.bin
Billycar11
Posts: 1600
Joined: Sun Aug 24, 2014 5:49 am

Re: ddrescue shows 0 errors/100% rescued on Libre-enabled drive, but makemkv fails with hashcheck errors

Post by Billycar11 »

kja70 wrote:
Thu Jun 03, 2021 12:00 pm

instructions for re-imaging the firmware that came with the drive? I have a tar file I created using sdftool dump before imaging Libre, but it's not clear to me what steps I take to restore those files to the drive. The tar file contains:

Code: Select all

fd_fwdate.bin
fd_sn.bin
inq.bin
rom_003000.bin
rom_1EC000.bin
rom_1F0000.bin
You don't need any of that you just flash it to a different BU40N Firmware with the sdf Tool but a different firmware is not going to change anything
Buy a UHD drive from the guide and how to video maker: https://www.makemkv.com/forum/viewtopic ... 20&t=17831
UHD Drives Guide: https://www.makemkv.com/forum/viewtopic ... 16&t=19634
Auto self flash kit Email me for one Billycar5924@gmail.com
kja70
Posts: 14
Joined: Mon Jun 15, 2020 7:40 pm

Re: ddrescue shows 0 errors/100% rescued on Libre-enabled drive, but makemkv fails with hashcheck errors

Post by kja70 »

Billycar11 wrote:
Thu Jun 03, 2021 3:12 pm
kja70 wrote:
Thu Jun 03, 2021 12:00 pm

instructions for re-imaging the firmware that came with the drive? I have a tar file I created using sdftool dump before imaging Libre, but it's not clear to me what steps I take to restore those files to the drive. The tar file contains:

Code: Select all

fd_fwdate.bin
fd_sn.bin
inq.bin
rom_003000.bin
rom_1EC000.bin
rom_1F0000.bin
You don't need any of that you just flash it to a different BU40N Firmware with the sdf Tool but a different firmware is not going to change anything
The previous poster suggested 'its also possible that libedrive itself mucks with the content' so I thought it was worth at least checking if ddrescue completes without error yet generates different disc images every time with the original firmware. Is the "old" folder in the firmware pack the original factory firmware for the drive? Should I be flashing with HL-DT-ST-BD-RE_BU40N-1.03-NM00000-211810241934.bin to see if I can replicate this issue with non-Libre firmware?
Billycar11
Posts: 1600
Joined: Sun Aug 24, 2014 5:49 am

Re: ddrescue shows 0 errors/100% rescued on Libre-enabled drive, but makemkv fails with hashcheck errors

Post by Billycar11 »

kja70 wrote:
Thu Jun 03, 2021 3:18 pm

The previous poster suggested 'its also possible that libedrive itself mucks with the content' so I thought it was worth at least checking if ddrescue completes without error yet generates different disc images every time with the original firmware. Is the "old" folder in the firmware pack the original factory firmware for the drive? Should I be flashing with HL-DT-ST-BD-RE_BU40N-1.03-NM00000-211810241934.bin to see if I can replicate this issue with non-Libre firmware?
No thats just old mk firmware.
You can use the de firmware i edited its all original except for 1 value change to allow downgrades
Or go to lgs website and put the latest 1.04 of but I'm telling you it's a waste of time and your just risking your drive for no reason
Buy a UHD drive from the guide and how to video maker: https://www.makemkv.com/forum/viewtopic ... 20&t=17831
UHD Drives Guide: https://www.makemkv.com/forum/viewtopic ... 16&t=19634
Auto self flash kit Email me for one Billycar5924@gmail.com
kja70
Posts: 14
Joined: Mon Jun 15, 2020 7:40 pm

Re: ddrescue shows 0 errors/100% rescued on Libre-enabled drive, but makemkv fails with hashcheck errors

Post by kja70 »

Billycar11 wrote:
Thu Jun 03, 2021 3:28 pm
You can use the de firmware i edited its all original except for 1 value change to allow downgrades
Or go to lgs website and put the latest 1.04 of but I'm telling you it's a waste of time and your just risking your drive for no reason
Sorry if I'm being dense--where do I find the de firmware? I see it mentioned in the pinned post on this forum, but it doesn't appear to be in the firmware pack ZIP file linked there.

And is there a risk to the drive of swapping that firmware in and out?

It's just odd that the drive is reporting no errors with ddrescue when there clearly are some -- something I've never seen with previous drives I've used.
Billycar11
Posts: 1600
Joined: Sun Aug 24, 2014 5:49 am

Re: ddrescue shows 0 errors/100% rescued on Libre-enabled drive, but makemkv fails with hashcheck errors

Post by Billycar11 »

kja70 wrote:
Thu Jun 03, 2021 3:44 pm
Billycar11 wrote:
Thu Jun 03, 2021 3:28 pm
You can use the de firmware i edited its all original except for 1 value change to allow downgrades
Or go to lgs website and put the latest 1.04 of but I'm telling you it's a waste of time and your just risking your drive for no reason
Sorry if I'm being dense--where do I find the de firmware? I see it mentioned in the pinned post on this forum, but it doesn't appear to be in the firmware pack ZIP file linked there.

And is there a risk to the drive of swapping that firmware in and out?

It's just odd that the drive is reporting no errors with ddrescue when there clearly are some -- something I've never seen with previous drives I've used.
It's under the "Unlocked Flashers, Downgrade Enabled Firmware and MK Firmware:" section the one that says de. Yes there is a risk if you flash the wrong thing
Buy a UHD drive from the guide and how to video maker: https://www.makemkv.com/forum/viewtopic ... 20&t=17831
UHD Drives Guide: https://www.makemkv.com/forum/viewtopic ... 16&t=19634
Auto self flash kit Email me for one Billycar5924@gmail.com
Coopervid
Posts: 239
Joined: Tue Feb 19, 2019 10:32 pm

Re: ddrescue shows 0 errors/100% rescued on Libre-enabled drive, but makemkv fails with hashcheck errors

Post by Coopervid »

Clean that disc as good as possible. Wash with liquid soap and use a microfiber cloth afterwards. If ripping still doesn't work try DVDisaster instead of ddrescue.
kja70
Posts: 14
Joined: Mon Jun 15, 2020 7:40 pm

Re: ddrescue shows 0 errors/100% rescued on Libre-enabled drive, but makemkv fails with hashcheck errors

Post by kja70 »

So restoring the firmware (to DE_flash_HL-DT-ST_BD-RE_BU40N_BU10.bin) seems to have fixed the problem. With the Libre firmware, makemkv failed entirely when it hit the bad area and stopped copying. With the original firmware, makemkv is able to power through -- it successfully copied the file, noting 1.65% corrupt and 98.33% correct (all other files complete without error). And using ddrescue shows only a single bad read (which it recovers) rather than hundreds or thousands. It seems like something with the Libre firmware was causing successive errors/failures right after the first bad read, which doesn't occur with the original firmware.

I'm happy to do further troubleshooting with the Libre firmware if there is anything else that it makes sense to try here.
puertorican
Posts: 6
Joined: Tue Aug 18, 2020 1:01 pm

Re: ddrescue shows 0 errors/100% rescued on Libre-enabled drive, but makemkv fails with hashcheck errors

Post by puertorican »

This issue happens in the LG drives because of what they call "Jamless play". It is technically not a problem, but a "firmware feature" that if the drive detects the disc is a Video DVD or Blu-Ray, and there are bad sectors, the drive sometimes will just skip those sectors, returning garbage data.

This is at the footer of the LG website: https://www.lg.com/us/blu-ray-burners-and-drives
Jamless play: Experience uninterrupted viewing with LG’s Jamless play feature that smooths out playback of damaged Blu-ray or DVD discs.
Therefore, even third-party tools may create a bad ISO or recover bad files because the drive will simply return garbage data on those sectors the drive seem to want to skip. This doesn't always happen, but there's a chance that it will happen.
kja70
Posts: 14
Joined: Mon Jun 15, 2020 7:40 pm

Re: ddrescue shows 0 errors/100% rescued on Libre-enabled drive, but makemkv fails with hashcheck errors

Post by kja70 »

Thanks for the explanation. Is there any workaround with either factory or libre firmware? One problem with this feature is you have no way to know which sectors are actually bad so you couldn’t use ddrescue to create a good image (either just by trimming and scraping one disc, or by combining the good data off of two discs). I suppose there’s probably some way to do it by performing repeat ddrescue, comparing the images, and marking sectors that provide different data each time as bad, but that would require a fair amount of work.
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