Limitations/requirements of iso contents and files

[misterhai]

I was hoping someone could give me a breakdown on the overall requirements of the iso files ventoy can boot and the limitations of ventoy.

Can I put an iso without a bootloader on ventoy partition?

Can ventoy boot with just an initrd/vmlinux/filesystem.squashfs on the iso, no syslinux/isolinux/grub?

[longpanda]

The ISO file must be bootable.
The simplest method is to test the ISO file with VM(VMware/VirtualBox).

[Reedemer0fSouls]

The ISO file must be bootable.

How do you make an ISO file bootable? More specifically, I need to make a live ISO image of the whole hard drive, which usually includes at least two partitions: the EFI partition, and the OS partition. If I make an ISO of the OS partition, that generally will not be bootable.