www.makemkv.com

However when I use makemkv the backup function is greyed out. Is this function not working for all disks or setups. The backup button is only available if the disc isn't opened. Run makemkv and then click the backup button without opening the disc. But it seems it was created not with large bluray ...

Create a folder backup with MakeMKV first. You can then create an image (.iso) file from the folder structure. Unfortunately, "Nero 4 for Linux" seems to be the only Linux program that supports creating UDF 2.50 filesystems, which is required for Blu-ray discs. It's an old program from 200...