As above the same issue degraded my system after reboot from 4.8.0-46 to 4.8.0-49.
Apr 25 17:08:40 nermal systemd-udevd[165]: Could not set Alias, MACAddress or MTU on eth1: Invalid argument
Apr 25 17:08:40 nermal kernel: eth0: Invalid MTU 9000 requested, hw max 68
As above the same issue degraded my system after reboot from 4.8.0-46 to 4.8.0-49.
Apr 25 17:08:40 nermal systemd-udevd[165]: Could not set Alias, MACAddress or MTU on eth1: Invalid argument
Apr 25 17:08:40 nermal kernel: eth0: Invalid MTU 9000 requested, hw max 68
/etc/systemd/ network/ bslav1. link
# -*- Systemd -*- xx:xx:xx: xx:xx
[Match]
MACAddress=
[Link]
Name=bslave1
MTUBytes=9000