There are two 'modes' for a BIOS
1. IBM BIOS compatible/CSM/Legacy - uses old 1981+ IBM legacy BIOS calls
2. UEFI - latest type of firmware
If you are UEFI-booting to Ventoy, the Ventoy Menu system will display e.g.
1.0.79 UEFI
at the bottom of the menu screen
This means you have booted in UEFI or EFI mode and so your payload files (ISOs, VHDs IMG files, etc.) must support UEFI booting.
If you run Ventoy in BIOS\Legacy mode (power-on - press F8/F11/F12/DEL/ESC (depends on BIOS) - and select non-EFI USB boot option) - then you will boot in Legacy\CSM mode.
Then 'old' payload files should work (Ventoy will display 1.0.79 BIOS in menu).
1. IBM BIOS compatible/CSM/Legacy - uses old 1981+ IBM legacy BIOS calls
2. UEFI - latest type of firmware
If you are UEFI-booting to Ventoy, the Ventoy Menu system will display e.g.
1.0.79 UEFI
at the bottom of the menu screen
This means you have booted in UEFI or EFI mode and so your payload files (ISOs, VHDs IMG files, etc.) must support UEFI booting.
If you run Ventoy in BIOS\Legacy mode (power-on - press F8/F11/F12/DEL/ESC (depends on BIOS) - and select non-EFI USB boot option) - then you will boot in Legacy\CSM mode.
Then 'old' payload files should work (Ventoy will display 1.0.79 BIOS in menu).