About GRUB2 Mode

• 1. Background

Compare with other boot tools (e.g. Rufus), Ventoy use different mechanism to boot an ISO file. Ventoy will emulate the ISO file as a CDROM to boot it. That's why sometime that an ISO file can boot OK with other tools to burn to USB but has problem when boot from Ventoy.
Actually, what Ventoy does is much like booting a CD with physical optical drive although physical optical drive is rarely used nowadays.
The mechanism used by Ventoy need to be supported by the firmware in the motherboard especially in UEFI mode. Normally there is no problem as long as the BIOS firmware of the motherboard meets the standard.
Alough the probability is relatively low, there do exist some buggy BIOS firmware that is not standard. In this case, Ventoy may have problems when booting an ISO file.

So Ventoy add GRUB2 Mode as an alternative for booting Linux ISO. Both Legacy BIOS and UEFI are supported.

Attention:
1. Use GRUB2 mode only when you run into problem with the default mode.
2. GRUB2 mode can only be used to boot Linux ISO which contains grub2 configuration file and can not be used to boot Windows/WinPE/Unix ...

• 2. How to use

Press Ctrl + r to enter GRUB2 mode. Press again to return default mode.
(Edit: since 1.0.80, you can also use GRUB2 mode in the secondary boot menu.)
(Edit: since 1.0.80, you can also press r without ctrl key to enter GRUB2 mode.)

There will be a GRUB2 tip in the bottom of the menu.


If you use a custom theme, the following hbox should be defined in the theme.txt to show the red tip.

+ hbox{ 
    left = 30%+200
    top = 95%-50
    width = 10%
    height = 25
    + label {text = "@VTOY_GRUB2_MODE@" color = "red" align = "left"} 
}

• 3. Supported Linux Distros

There must be grub2 configuration file inside the ISO file. Generally, the path of the grub2 configuration file is one of the following:

/boot/grub/grub.cfg
/EFI/BOOT/grub.cfg
/EFI/boot/grub.cfg
/efi/boot/grub.cfg
/grub/grub.cfg
/EFI/BOOT/BOOTX64.conf
/EFI/debian/grub.cfg