Legacy support ?

[victorbnl]

Hello! This seems like a ridiculous question, but I searched a lot and didn't find an answer. So basically I have a computer that doesn't support UEFI. And I have a ISO that doesn't support it, too, Hiren's.BootCD.15.2.iso (it does No bootfile found for UEFI!).
For both these use cases I'd like to boot the ISOs as legacy.
Note : I don't want Ventoy to boot as legacy, it already does that, and I know it, I want the ISOs to boot as legacy.

In #313 you say the following :

Yes.
Ventoy virtualizes the ISO as a cdrom device and boot it.
So if the ISO doesn't support UEFI mode itself, the boot will fail.

What does it mean? Does it mean that Ventoy does not support booting legacy ISO at all?

Do you know how can Ventoy support legacy booting, if it does?

[TechCare-Aus]

@victorbnl - when you make a Ventoy USB you have the option of MBR or GPT. Use MBR. It has 5 start legacy boot mode support. See more here - https://www.ventoy.net/en/doc_mbr_vs_gpt.html

I've used Hiren Boot CD before, also using the new Hiren Boot CD based on WIN10PE (I think it is called).

My advice is to just give it a red hot go. Use a USB that you can wipe (it will delete everything - so backup anything you want to keep).

Keep in mind that if you want to boot via UEFI and a system that is running in that mode you will NEED to change the bios to allow legacy boot. Sometimes when you open the boot menu (different option for each motherboard manufacturer) you get the option to select legacy or UEFI boot devices. Google yours.

[ventoy]

Ventoy supports both UEFI mode and Legacy BIOS mode.

I don't want Ventoy to boot as legacy

It's your BIOS firmware in your machine that decides to boot Ventoy in UEFI mode or Legacy BIOS mode.
If you don't want to Ventoy to boot as legacy, you must change your BIOS to UEFI mode.
If your BIOS only support legacy (doesn't support UEFI) then Ventoy will only be booted in Legacy BIOS mode in your machine.

Most of the ISO files support both legacy boot and UEFI boot.
Some ISO files only support legacy boot and don't support UEFI boot.
So almost all the ISO files support legacy boot.

Ventoy supports boot an ISO file in legacy bios mode if it support legacy boot.
Ventoy supports boot an ISO file in uefi mode if it support uefi boot.
Ventoy doesn't support boot an ISO file in uefi mode if it doesn't support uefi boot itself.

[steve6375]

It is sometimes possible to UEFI-boot to an MBR-only ISO if you use grub2 to load the kernel and initrd files.
You will need to make a special grub2 menu
e.g..
http://rmprepusb.blogspot.com/2021/02/how-to-uefi64-boot-to-antiviruslivecd.html

[victorbnl]

Ok so I only need to turn the option for legacy boot in the bios. Understood, thanks!!

[Wmvare]

Tengo una Surface Pro 3.
No hay manera de hacer correr el Ventoy, si no desactivo en la Bios la protección Legalicy.
Tampoco en mi portátil Mountain, siempre hay que desactivar en la Bios la protección Legalicy.
Es una pena que pase esto, pués el programa Ventoy es muy útil, aunque con los nuevas Bios se quedará obsoleto.

[victorbnl]

¿Y si pruebas con GPT? Quizás sea que tu BIOS no permita encender el sistema con UEFI si uzas MBR.