Booting from an existing Linux installation using GRUB

If you have an existing Linux system where you are unable to use iPXE or boot from a disk image, but you can see the GRUB menu on boot, you can boot into netboot.xyz using grub-imageboot.

On Debian/Ubuntu

# Install grub-imageboot
apt install grub-imageboot

# Download netboot.xyz ISO
mkdir /boot/images
cd /boot/images
wget https://boot.netboot.xyz/ipxe/netboot.xyz.iso

# Update GRUB menu to include this ISO
update-grub2
reboot

On Red Hat Based Systems

yum install syslinux wget -y
cp /usr/share/syslinux/memdisk /boot/memdisk
mkdir /boot/images
cd /boot/images
wget https://boot.netboot.xyz/ipxe/netboot.xyz.iso
ln -s /usr/share/grub/grub-mkconfig_lib /usr/lib/grub/grub-mkconfig_lib
#Download iamgeboot config file
wget https://raw.githubusercontent.com/formorer/grub-imageboot/529ac5d2bf91e7da8c31b9e15f37702127bddc1c/bin/60_grub-imageboot -O /etc/grub.d/60_grub-imageboot
chmod 755 /etc/grub.d/60_grub-imageboot
grub2-mkconfig -o /boot/grub2/grub.cfg
reboot

After reboot, select "Bootable ISO Image: netboot.xyz" in the GRUB menu.

If the GRUB menu disappears too quickly, you may need to edit /etc/default/grub and increase the GRUB_TIMEOUT. Run update-grub2 any time you modify this file.