Hi I run into the same issue trying to boot a linuxmint 20 (and also ubuntu 20). After some digging, it appears that the Unable to find a live file system on the network show up because do_nfsmount() from the casper script chipped inside the initrd isn’t able to mount correctly the nfs share.
I extracted (using unmkinitramfs) the nfsmount binary to test it standalone on a working nfs share using the same option provided by this casper script (nfsmount -o nolock -o ro ${NFSOPTS} ${NFSROOT} ${mountpoint}) which work well.
I also tried to use the initrd from a linuxmint 19 to load the linuxmint 20 iso and… it worked but without any big surprise I ran into issue while I tried to install the os.
The differences between mint19 and mint20 are some check performed after nfsmount call:
do_nfsmount from mint 20
do_nfsmount() {
rc=1
modprobe "${MP_QUIET}" nfs
if [ -z "${NFSOPTS}" ]; then
NFSOPTS=""
else
NFSOPTS=",${NFSOPTS}"
fi
[ "$quiet" != "y" ] && log_begin_msg "Trying nfsmount -o nolock -o ro ${NFSOPTS} ${NFSROOT} ${mountpoint}"
# FIXME: This while loop is an ugly HACK round an nfs bug
i=0
while [ "$i" -lt 60 ]; do
if nfsmount -o nolock -o ro${NFSOPTS} "${NFSROOT}" "${mountpoint}"; then
if is_casper_path $mountpoint && matches_uuid $mountpoint; then
rc=0
else
umount $mountpoint
fi
break
fi
sleep 1
i="$(($i + 1))"
done
return ${rc}
}
do_nfsmount from mint 19
do_nfsmount() {
rc=1
modprobe "${MP_QUIET}" nfs
if [ -z "${NFSOPTS}" ]; then
NFSOPTS=""
else
NFSOPTS=",${NFSOPTS}"
fi
[ "$quiet" != "y" ] && log_begin_msg "Trying nfsmount -o nolock -o ro ${NFSOPTS} ${NFSROOT} ${mountpoint}"
# FIXME: This while loop is an ugly HACK round an nfs bug
i=0
while [ "$i" -lt 60 ]; do
nfsmount -o nolock -o ro${NFSOPTS} "${NFSROOT}" "${mountpoint}" && rc=0 && break
sleep 1
i="$(($i + 1))"
done
return ${rc}
}
I tried to add some debug to identify what is going wrong but I couldn’t manage to “repack” the extracted initrd into a clean working one ending up on a kernel panic (I spend quite some time trying out, initrd archive structure seems to have recently evolve to chip intel and amd firmware inside). The only changed I made was adding some echo into the casper file. If someone manage to do so, it would be interesting to check what is_casper_path and matches_uuid does and return.
As I wasn’t able to produce a custom initrd, I tried to configure a http server to serve the iso on similar way as suggested on the comment bellow by @pacman366. But ubuntu/mint desktop iso are quite big (2GB) and 4GB ram isn’t enough to be able to extract the iso. I also tried to boot from http following these instructions: https://www.plop.at/en/ploplinux/live/networkboot-linux.html#pxel61 without any success. I’m not sure how | in the url work (no request received on the nginx web server).
I’d really like to be able to fix this, any idea/help would be appreciated