@khurshid-alam
Just downloaded Xubuntu 18.10 daily to have a look. There is no initrd.lz in casper any more, but just initrd, without the .lz extension. Its OK as in Linux, you really don’t need an extension as in Windows. Here with the Xubuntu live iso, we are sort of not given the chance to find out what compression is used to pack that “initrd.” Actually, what compression was used is not a big deal, if you want to create a live iso, 1) you can use the vmlinuz and initrd as they are, or 2) add updated/upgraded ones without any extensions. (Or, you can add any extension you want, even .exe… he, he, just for fun…)
Most probably, your Ryzen 5 is on UEFI, so if you boot Xubuntu 18.10 live, it’d use /boot/grub/grub.cfg to look for what to boot with. This is what it tells,
if loadfont /boot/grub/font.pf2 ; then
set gfxmode=auto
insmod efi_gop
insmod efi_uga
insmod gfxterm
terminal_output gfxterm
fi
set menu_color_normal=white/black
set menu_color_highlight=black/light-gray
set timeout=5
menuentry “Try Xubuntu without installing” {
set gfxpayload=keep
linux /casper/vmlinuz file=/cdrom/preseed/xubuntu.seed boot=casper quiet splash —
initrd /casper/initrd
}
I’ll give you a detailed how-to tomorrow (or on Monday) on manipulating the live iso and creating your own, when I’d be back using the other laptop.