Well, this was illuminating. After Roxio NXT 4 wrote the image, I did a verify of the contents in the other application. The files passed verify on both layers. So, I performed a manual Verify of the ISO that Roxio NXT 4 burned with ImgBurn, with verification against contents in the ISO file. ImgBurn Verify passed!
So, the inescapable conclusion is there's something going wrong when ImgBurn switches layers writing Verbatim BD DL media in an LG drive when it's burning an ISO file. I can't see why that would happen, but it sure seems to be the case. Verify doesn't fail when ImgBurn doesn't write the ISO. ImgBurn Verifies pass when an on the fly write is performed on these media in an LG drive. So, what could be going wrong with writing from an ISO file to a Verbatim BD DL disc in an LG drive with ImgBurn?
I realize ImgBurn only burns what it's given. And it only sends commands to drives. How the drive interprets those commands isn't up to ImgBurn, I know that. But, what could be the cause in this case? It is repeatable as I never burned anything but ISO's with ImgBurn in the LG before with Verbatim BD DL media. And it happened on 2 different Dell machines, and the OP's machine. And it happened on 2 different kinds of LG drives in my tests, with about 10 burns tested in the past.
My LG drive also fails when writing ISO's to Verbatim 6x DVD-RW. I wonder if I repeated this test with Roxio NXT 4 as the writer of the image file in my LG and used ImgBurn to perform a Verify on it if it would pass? Something to try if I can remember do it.
Another thing to ponder. For a year, I've been saying Pioneer borked writing to Ritek 8x DVD+RW with its 1.34 firmware. ImgBurn always failed Verify on them. I think I'll try the Roxio NXT burn/ImgBurn manual Verify test in that scenario. See if it's ONLY the firmware writing these discs that causes the problem.
So, it seems my initial advice I've been giving people over the years is incorrect. LG drives apparently aren't lousy writers when it comes to Verbatim BD DL media. They're just lousy at interpreting the commands ImgBurn sends them when it writes an ISO file to that media, it seems.
No, I can verify (HA!) that the firmware IS borked in the Pioneer. Roxio NXT failed right at the start of Verify as did ImgBurn when Verifying the contents.
Edited by dbminter, 15 December 2017 - 04:44 AM.