www.makemkv.com

I trying 1.01 right now and am receiving a bit slower speeds:
https://i.imgur.com/tsg7hle.png

I would have tried BU40N-1.00 but I did not see it in the 'old' directory:
https://i.imgur.com/Cp3RRfi.png
Though it could be there.. my eyesight is very poor because of my disabilities, one of which ...

That is what I received on the firmware mk 1.04 (note screenshot above) ... interesting the difference between 1.03 / 1.04

Since you suggested it, I tested it 8)

Interesting to note that the date specified on the firmware is 2118... Must be some active tachyon fields in the drive!

Drive Information
OS device name: E:
Current profile: BD-ROM
Manufacturer: HL-DT-ST
Product: BD-RE BU40N
Revision: 1.03
Serial number ...

You asked for the MakeMKV & LibreDrive info. Here is what it looks like after the flash:

Drive Information
OS device name: E:
Manufacturer: HL-DT-ST
Product: BD-RE BU40N
Revision: 1.04
Serial number: 811HS013514
Firmware date: 2120-05-06 11:42
Bus encryption flags: 17
Highest AACS version: 78 ...

I figured it out earlier today and the drive works just fine (and I watched Wargames in 4kUHD 8) )

1. The correct firmware was within Admin Mike's MK collection (not the 'everything' collection that I tried.. or if it was I missed it)

HL-DT-ST-BD-RE_BU40N-1.04-NM00500-212005061142
https://i.imgur ...

I attempted to flash this 'new' BU40N drive with the firmware options that I could find in the forum, each received an error. My guess is that this drive is not the same as the other 40N versions, but of course am not sure so I have included a picture as reference. Interestingly, notice in the photo ...