Booting ISO via Grub2.cfg (CentOS) Help

RemoteControl

One of my providers delivered a server with the wrong OS on it and the support likes disappearing for weeks on end.

Current OS is CentOS7 Core kernel3.10.0-1062.9.1.el7.x86_64

I have been going crazy trying to get the correct OS installed on it. I have temporary IMPI access for 24hours but I am not getting anywhere.

I have tried:
menuentry "Ubuntu ISO" {
set isofile="/root/ubuntu-18.04.3-live-server-amd64.iso"
loopback loop (hd0,2)$isofile
linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=$isofile nopro
initrd (loop)/casper/initrd.lz
}

END /etc/grub.d/40_custom

However I keep getting an error saying that I must boot the kernel first. Not sure what I am doing wrong, but I've been able to boot ISOs directly via grub before via same method.

Can someone point me in the right direction here before my 24hr temp IMPI expires?

Is there any other way to do a NetInstall or PXE boot? Also the IMPI interface is by Raritan (multi-platform client MPC).

Thanks!

RemoteControl

See answer https://forums.centos.org/viewtopic.php?t=61774