From the document you can see that ventoy will create a virtual disk from the iso file and boot it. But the virtual disk is only on BIOS(Legacy or UEFI) level. In most case it works only in bootloader period. Most of the morden OS's kernels will use their driver to access hardware after boot, so the virtual disk will not be visible to them. In normal case, the OS will search all the hardware storage media(CDROM/USB/HD ...) to find the source medium. But with ventoy they will not find such medium because there is no such physical media and they don't know that they were booted from a virual disk. In order to support that ventoy must do some hook before boot. But the hook is really a hard work because there are so many different OS distros and so many special cases.


In fact, ventoy saves the information to runtime memory before booting and provides a tool to get the information. In this way, the OS can know that they were booted from a virtual disk created by ventoy and can also know which iso file in which disk is the right image. Based on that, the OS can find the source medium successfully and continue to boot. Of course the tool will get nothing if they were not booted by ventoy, in that case they can go as originally. So things will become very simple if the OS distros integrate this tool and do the compatible processing. Ventoy will no longer need to do the boring hook.
Another thing is that how ventoy knows the OS in the iso file is "Ventoy Compatible" ? Ventoy gives some ways for the OS distros to chose to mark themselves.

I call such an OS distro or iso file as "Ventoy Compatible" if it contains the process mentioned above.

Compatible Distros

The concept of "Ventoy Compatible" is introduced by myself and I hope that it can be widely supported someday.

Distro Note
a1ive / grub2-filemanager v7.1.0+ grubfm_multiarch.iso
U盘魔术师 (USM) Offical release since 2020/05/30
Hikari PE Offical release since V8.1+

For OS

For more detailed descriptions about "Ventoy Compatible", you can refer to the relate documents in Document.