NAS326 does not boot reliably (1 reply)

Hi all,
I'm running Debian 9.9 with kernel 4.19.1-mvebu-tld-1 on my NAS326 box and I am very happy with it,
excluding one problem: The box does not boot reliably. Every second (or third, I was not able to figure it out clearly) time I shutdown the box with

shutdown -h now

and try to boot the box again, the box remains in a state where it is not reachable through samba/ssh/etc.
While in this state, all three front leds are shining continuosly.
When I "switch off" the box by removing the power plug and booting up again, it works.
Attached are my u-boot envs. Unfortunately I do not have a serial interface available.
Anybody out there experiencing a similar problem?

Michael