When 4K Ultra HD Blu-ray discs were released, they came with the AACS 2.0 encryption standard. This standard was designed to be unbreakable on PC drives. However, the community discovered that certain older firmware versions on specific LG and ASUS drives had "bugs" or backdoors that allowed the drive to circumvent these restrictions.
Firmware version 1.00 for the BU40N is the release. Later updates (1.01, 1.02, 1.03, and 1.14) were pushed by LG specifically to patch these vulnerabilities. Here is what version 1.00 offers that newer firmware does not: 1. Full LibreDrive Support LibreDrive is a feature integrated into MakeMKV. When a drive has "LibreDrive enabled," the software takes direct control of the drive’s firmware, bypassing the host's operating system limitations. With firmware 1.00, the BU40N achieves "LibreDrive Friendly" status, allowing it to read the raw encrypted data from any 4K disc regardless of region or AACS version. 2. No "Sleep Bug" Newer firmware versions suffer from an infamous "sleep bug." If the drive sits idle for 20 seconds while reading a UHD disc, it enters a low-power state. To wake it up, MakeMKV must send a reset command, often causing the rip to freeze or fail. BU40N 1.00 firmware does not have this sleep bug. 3. Direct UHD Reading without "Friendly" Drive workarounds Unlike desktop drives (e.g., ASUS BW-16D1HT) that require specific "friendly" firmware versions (like 3.02 or 3.10), the BU40N on 1.00 works seamlessly with any UHD disc up to BD-100 (triple layer). 4. Speed Unlocking Users consistently report that the BU40N on 1.00 rips faster than its rated specification. While the drive is rated for 4x BD-ROM reading, users often sustain 6x to 8x read speeds on UHD discs because 1.00 lacks the artificial speed throttling present in later revisions. The Risks: Why You Cannot Just "Update" to 1.00 Here is the crucial catch: LG has blocked downgrading. bu40n 1.00 firmware
This article is for educational purposes and digital backup of legally owned media only. Circumventing DRM may violate laws in your jurisdiction. When 4K Ultra HD Blu-ray discs were released,
Most BU40Ns can be flashed directly. Connect the drive. Ensure no disc is inside. Firmware version 1
Do not use LG’s official website. You need the community tools found on the MakeMKV forums (specifically the "Ultimate UHD Drives Flashing Guide" thread).