I have a laptop with dead USB ports (old thinkpad t42p) that I use in QA-testing Ubuntu flavors.
I download the daily ISOs onto the local HDD to a location I selected.
The following entries were then added to /etc/grub.d/40_custom
(this is a snippet only as it lists many other ISO options)
menuentry "Lubuntu QA testing 18.04.4 ISO noPAE" {
set root=(hd0,7)
set isofile="/lubuntu-18.04.4-desktop-i386.iso"
loopback loop (hd0,7)/lubuntu-18.04.4-desktop-i386.iso
linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=/lubuntu-18.04.4-desktop-i386.iso forcepae --forcepae --
initrd (loop)/casper/initrd
}
menuentry "Lubuntu QA testing 18.04.5 ISO noPAE" {
set root=(hd0,7)
set isofile="/lubuntu-18.04.5-desktop-i386.iso"
loopback loop (hd0,7)/lubuntu-18.04.5-desktop-i386.iso
linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=/lubuntu-18.04.5-desktop-i386.iso forcepae --focepae --
initrd (loop)/casper/initrd
}
menuentry "Xubuntu QA testing 18.04.5 ISO noPAE" {
set root=(hd0,7)
set isofile="/xubuntu-18.04.5-desktop-i386.iso"
loopback loop (hd0,7)/xubuntu-18.04.5-desktop-i386.iso
linux (loop)/casper/vmlinuz boot=casper iso-scan/filename=/xubuntu-18.04.5-desktop-i386.iso forcepae --focepae --
initrd (loop)/casper/initrd
}
Note: The 'forcepae --forcepae' is required only because this really old pentium M device requires those kernel lines to boot. It's actually handy, as on other (prehistoric pentium) devices I have to manually type that detail onto the kernel line for the laptops with working thumb-drives on each QA-test boot.
You'll have to change the ISO files to match your system, plus location of where you stored the ISO files. Mine were in / of sda7. This is intended as example only.
To re-create the grub file use the command sudo update-grub
.
grub
so it lists that option, and install from that (I've done it where I don't have working USB ports). – guiverc Sep 03 '20 at 12:14