Unlike newer "MK" (MakeMKV-specific) patched firmwares like 1.03-MK or 1.04-MK, the 1.00 "DE" (Downgrade Enabled) version is widely compatible with a broader range of software, including DVDFab and Xreveal .
The BU40N is an ultra-slim laptop-style drive. Because it lacks a dedicated internal fan and has a small physical footprint, it generates significant heat during the 45–90 minute process of ripping a 4K disc.
High temperatures can expand internal components slightly, leading to "ScSI Error" or "Read Offset" failures mid-rip. bu40n 100 firmware hot
Excessive heat can lead to thermal throttling , causing the drive to slow down from 6x to 2x or even stall completely.
Never cross-flash a BU40N with firmware from a desktop drive (like the WH16NS60), as this will permanently brick the slim drive. Ultimate UHD Drives Flashing Guide Updated 2021 : r/makemkv Ultimate UHD Drives Flashing Guide Updated 2021 :
Firmware version 1.00 is considered the "holy grail" for the LG BU40N (and rebadged versions like Archgon or Verbatim slim drives).
Open MakeMKV and check the "Drive Information" tab. It should list the product as HL-DT-ST BD-RE BU40N . restricted firmware (like 1.04 or 1.05)
If your drive came with a newer, restricted firmware (like 1.04 or 1.05), you may need to "downgrade" it to regain UHD capabilities.
To keep the drive "cool," enthusiasts often use it in an external enclosure with better airflow or place the drive on a laptop cooling pad during long sessions. How to Get Firmware 1.00
Version 1.00 is a "UHD-friendly" firmware that allows software like MakeMKV to bypass AACS 2.0/2.1 protection on 4K Blu-rays.