The BU40N holds a specific place in the enthusiast community (notably on forums like MyCE or VideoHelp) because of its potential for customization. The 1.00 firmware is often the target for modification.
Most modern Blu-ray drives ship with firmware that blocks the "LibreDrive" features required to read the raw data on 4K UHD discs. Version 1.00 is a "friendly" firmware that bypasses these restrictions. bu40n 1.00 firmware