Cloned Jessie image fails to acquire a dhcp address

[framp]

I have a nasty issue I'm looking for help: I wrote a backup script for Raspberry called raspiBackup. It works fine for me and therefore I decided to publish it to the community. It's already used by a lot of people and helped already the community to recover from SD card failures.

Recently I was noticed the restored image doesn't get an IP address via DHCP. I was able to reproduce the issue and tried to find the root cause but without success

It looks like the root cause is somehow related to:
1) Source Image is Jessie. No issue with Wheezy (systemd ?)
2) Backup is created and restored with tar. If a dd or rsync backup is used everything works fine
3) dhcpcd5. If networkd is used everything works fine.

I initially posted my issue here 4 weeks ago but didn't get any help to solve the issue or at least to understand where the issue comes from That's why I'm looking for help in this forum now. Please visit the link above to read all the details I provided for my issue in order to understand my issue in detail.

I added a link to this post in the initial post to cross link the identical questions. From now on I see this post to be the primary post for my issue.

Would be great to get some hints what's actually the root cause for the issue. If you need any additional information just ask for it.

[epoch1970]

Something revolving around dhcpcd's use of DUID maybe?
https://wiki.archlinux.org/index.php/dh ... DHCP_lease (and Tips & tricks below)

I don't use dhcpcd5 very much myself.

[framp]

That's a good link . I'll check the next days whether this is the root cause.

But nevertheless it's strange because the image saved and restored with rsync or dd receives a DHCP IP address. But an image saved and restored with tar doesn't even it's also a full backup and restore

[framp]

I restored a tar backup which bootet but didn't receive a DHCP IP. Then I tried following steps:
1) deleted /var/lib/dhcpcd/dhcpcd-interface.lease and rebootet. no success
2) deleted /etc/dhcpcd.duid and rebootet. No success
3) commented out require dhcp_server_identifier. in /etc/dhcpcd.conf. No success
4) added -t 0 in /etc/systemd/system/dhcpcd@.service.d/timeout.conf and rebootet. No success