I'm using a Pine 64 LTS. For this I have downloaded the SoPine images

           Armbian_21.08.1_Pine64so_buster_current_5.10.60.img and

           Armbian_21.08.1_Pine64so_focal_current_5.10.60.img

Both images boot normally (including network connection), but after the update (apt update, apt upgrade) no IP4 network connection is established for eth0.

 

For help I am very grateful for any help.

 

I managed to reconnect via DHCP again with the following steps:

 

Insert these lines in /etc/network/interfaces

auto eth0
iface eth0 inet dhcp
  pre-up ifconfig $IFACE up
  pre-up ethtool -s $IFACE speed 100 duplex full autoneg off

 

and change the line in /etc/NetworkManager/NetworkManager.conf to

[ifupdown]
managed=false

 

First boot after installing a new image, I also had no connection on eth0. Error was that there was no carrier. What fixed it, was replugging the UTP connectors on both side of the cable.