Ensure you have MakeMKV installed in the default location (C:\Program File (x86)\MakeMKV).cinerama19806 wrote: Thu Jan 15, 2026 10:40 pm Many thanks for all your efforts here. Hopefully this one's an easy fix and I'm just missing something simple trying to use the SDFtool Flasher. (Side note: I previously successfully flashed an Asus drive but I don't remember when or how, and that drive has pretty much given up the ghost for burning and hasn't successfully opened a 4K disc in ages (lots of grinding) even though it's Libradrive enabled.)
I've now purchased a Verbatim external 4K drive from Amazon (not too many options out there now) which Makemkv is reading as
Drive Information
OS device name: D:
Manufacturer: HL-DT-ST
Product: BD-RE BU40N
Revision: 1.05
Serial number: MO6PAKA5435
Firmware date: 2124-04-23 13:47
Bus encryption flags: 17
Highest AACS version: 82
LibreDrive Information
Status: Possible, not yet enabled
Drive platform: MT1959
When I open the SDFtool Flasher for this drive I get the same error previously noted: StartIndex cannot be less than zero (which I believe is not a "show stopper". Once I advance to the software window, I don't see a drive available for flashing (i.e. there's no option available in the pulldown menu for the drive. I don't know if it matters, but I've removed my previous Asus drive as an option and have assigned the new drive the "D" drive letter. (I believe I'm OK with the flash version needed and it's available to me from the "all you need firmware pack" (LG Slim BU40N) - but I can't get there without being able to select a drive.) Please let me know what I'm missing here.
Ensure there is no disc in the drive and the tray is closed.
If the drive still isn't seen, try changing ports. Best to use USB ports direct from the motherboard, not case ports. An AC self-powered USB hub of at least 24w is even better.
Once the drive is showing in SDFtool Flasher, flash it to BU40N 1.03-MK.