As you might expect, when I tried to rip it, I got a ILLEGAL REQUEST:COPY PROTECTION KEY EXCHANGE FAILURE - KEY NOT PRESENT' notification.
I've looked up the excellent drive flashing guide, but as someone who has no knowledge about any of this stuff, it kind of made my head spin.
I did eventually manage to figure out that I probably need the HL-DT-ST-BD-RE_BU40N-1.03-NM00000-211810241934 firmware file, but I'm just posting this because I want to double-check before I try anything and accidentally brick my drive.
Drive Information
OS device name: /dev/rdisk2
Current profile: BD-ROM
Manufacturer: HL-DT-ST
Product: BD-RE BU40N
Revision: 1.01
Firmware date: 2119-10-16 10:32
Bus encryption flags: 1F
Highest AACS version: 78
LibreDrive Information
Status: Possible (with patched firmware)
Drive platform: MT1959
Harware support: Yes
Firmware support: No
Firmware type: Original (patched version available)
Firmware version: 1.01
DVD all regions: Possible (with patched firmware)
BD raw data read: Possible (with patched firmware)
BD raw metadata read: Possible (with patched firmware)
Unrestricted read speed: Possible (with patched firmware)