GRML iPXE etboot from HTTP (without NFS)

GRML_ISO=https://download.grml.org/grml64-small_2020.06.iso
 
# Downlaod Grml image
wget ${GRML_ISO} -qO /tmp/${GRML_ISO##*/}
 
# Mount ISO
mount /tmp/${GRML_ISO##*/} /mnt/ -o loop
 
# Copy GRML files to tftpboot directory
mkdir -p /var/lib/tftpboot/live/grml/64-small
cp /mnt/boot/grml64small/{initrd.img,vmlinuz} /var/lib/tftpboot/live/grml/64-small/
cp /mnt/live/grml64-small/grml64-small.squashfs /var/lib/tftpboot/live/grml/64-small/
 
# Umount ISO
umount /mnt
 
# Create iPXE config
cat << EOF > /var/lib/tftpboot/grml.pxe
#!ipxe
 
initrd http://${next-server}/grml/initrd.img
chain http://${next-server}/grml/vmlinuz boot=live fetch=http://${next-server}/grml/grml64-small.squashfs apm=power-off nomce noprompt noeject grml2ram vga=791  lang=de ssh=grml console=tty0 console=ttyS0,115200n8lang=de ssh=grml
EOF
 
cd /var/lib/tftpboot
ln -s grml.pxe default