Re: arm64 and isohybrid
> If I specify "-c isolinux/boot.cat" too, that fixes
That's surprising. Can you surely switch forth and back
between mounatble and unmountable by this option ?
Option -c just gives the El Torito catalog a file name.
The catalog file is not involved in booting from
USB-stick or in the hard-disk-like partitioning of the image.
> efi.img is being modified otherwise, it seems?
El Torito boot images get modified only if options
-boot-info-table or --grub2-boot-info are present.
You can check this by comparing boot/grub/efi.img of
the ISO with boot/grub/efi.img in the input file tree
on hard disk.
Have a nice day :)