www.makemkv.com

I suppose the current userbase for MakeMKV on ARM64 is minimal, but I'm hoping the following bug can still be fixed, as recent changelogs include ARM changes.

For some reason (others have confirmed it), UHD Blu-rays always error out at the start and require you to submit the dump for keys. Under Windows X86, the identical disc works perfectly.

I also tried manually supplying a keydb.cfg, but it still didn't decrypt.

I tested it for 2 discs, and my experience with MakeMKV on arm64 has been fine. It works exactly as it does on x86. Here I'm using an Orange Pi 5+ with Ubuntu 24.04, able to backup a 4K disc with an external drive.

Is it possible your distro is blocking outbound network access?
And can you describe your setup? What blu-ray drive, board/SoC, distro, etc. are you running?