The (specifically the "Downgrade Enabled" or "DE" version) is considered the "gold standard" for enthusiasts who rip 4K Ultra HD (UHD) Blu-rays. While newer official firmwares (1.01–1.05) often block unauthorized reading of UHD discs to satisfy DRM requirements, the 1.00 DE firmware removes these restrictions, turning the BU40N into a "UHD-friendly" drive. Why Firmware 1.00 is Recommended
If your LG BU40N reports in MakeMKV, you have a golden drive . Never update it. It will handle 4K UHD ripping better than almost any other slim drive on the market.
Physically disconnect the drive from power (unplug SATA power or USB cable), wait 10 seconds, and reconnect.
To bypass these artificial restrictions, enthusiasts use specialized flashing utilities to revert the drive back to the legendary (often labeled as DE_LG_BU40N_1.00 ). This unencrypted, data-read-friendly firmware transforms the hardware into a fully compliant "LibreDrive". Why Version 1.00 is the Gold Standard bu40n 1.00 firmware
MakeMKV, the most popular tool for backing up Blu-rays, features a technology called "LibreDrive." LibreDrive allows the software to take direct control of the optical drive, bypassing the traditional host authentication and region locking. However, newer firmwares (1.03, 1.04, and later) include host revocation lists that block MakeMKV’s ability to enable LibreDrive. is the last firmware version released before these lockdowns were fully implemented. It offers full, unrestricted LibreDrive support out of the box.
: Some users have reported that versions newer than 1.00 (even modded ones) struggle to reliably burn 100GB BD-XL discs, making 1.00 the more stable choice for both reading and writing large media.
: Some users report that version 1.00 avoids "odd issues" found in newer versions, such as difficulties reliably burning 100GB BD-XL discs or random ripping stalls. Flashing and Downgrading The (specifically the "Downgrade Enabled" or "DE" version)
Reverting your LG BU40N to the turns an ordinary, restricted laptop drive into an elite media archiving tool. By unlocking LibreDrive capabilities, you gain complete control over your physical media library, allowing you to future-proof your 4K movie collection in uncompressed digital formats. To help you get started with the flash, tell me:
This is often a "sleeping brick." Unplug the drive from power and USB for a full 60 seconds. Plug it back in. If still dead, you may have attempted to flash 1.00 onto a drive with native 1.05+ firmware, which is not possible via standard methods.
If your drive currently has a higher version (like 1.01, 1.02, or 1.05), you may need to follow specific steps to "downgrade" back to 1.00: Encrypted Firmware Never update it
The 1.00 firmware is optimized for faster data reading compared to later, restricted versions, significantly reducing the time it takes to backup a 100GB 4K disc.
The LG BU40N running remains a gold standard for digital preservation enthusiasts. By avoiding modern, restrictive firmware updates—or actively downgrading back to 1.00—you unlock the full hardware potential of your drive, transforming it from a locked consumer accessory into an unrestricted powerhouse for 4K media archiving.
(This is your current firmware version, e.g., 1.03)