Comment 4 for bug 1626158

OK, i recreated with simple:
 uvt-kvm create sm-y1 release=yakkety
 uvt-kvm ssh --insecure sm-y1
 % echo "root:passw0rd" | sudo chpasswd
 % sudo apt-get update && sudo apt-get dist-upgrade && sudo reboot
 ...

then at the virsh console i see the fail, log in and:

root@sm-y1:~# mount /dev/disk/by-label/UEFI /mnt
[ 224.272443] FAT-fs (vda15): codepage cp437 not found
mount: wrong fs type, bad option, bad superblock on /dev/vda15,
       missing codepage or helper program, or other error

       In some cases useful info is found in syslog - try
       dmesg | tail or so.
root@sm-y1:~# dmesg | tail
[ 4.468785] call_modprobe: nls_utf8 2
[ 4.473050] ISO 9660 Extensions: RRIP_1991A
[ 4.501051] audit: type=1400 audit(1474476002.188:6): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/sbin/dhclient" pid=543 comm="apparmor_parser"
[ 4.501270] audit: type=1400 audit(1474476002.188:7): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=543 comm="apparmor_parser"
[ 4.501471] audit: type=1400 audit(1474476002.188:8): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/usr/lib/NetworkManager/nm-dhcp-helper" pid=543 comm="apparmor_parser"
[ 4.501656] audit: type=1400 audit(1474476002.188:9): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/usr/lib/connman/scripts/dhclient-script" pid=543 comm="apparmor_parser"
[ 4.514047] audit: type=1400 audit(1474476002.200:10): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/usr/bin/lxc-start" pid=566 comm="apparmor_parser"
[ 224.270568] FAT-fs (vda15): utf8 is not a recommended IO charset for FAT filesystems, filesystem will be case sensitive!
[ 224.271666] call_modprobe: nls_cp437 2
[ 224.272443] FAT-fs (vda15): codepage cp437 not found
root@sm-y1:~# find /lib/modules/ -name "*cp437*"
root@sm-y1:~# ls /lib/modules/
4.4.0-9136-generic 4.8.0-11-generic
root@sm-y1:~# find /lib/modules -name "nls_*"
/lib/modules/4.4.0-9136-generic/kernel/fs/nls/nls_iso8859-1.ko
/lib/modules/4.8.0-11-generic/kernel/fs/nls/nls_iso8859-1.ko