I received mine today and also had the overheating problems as mentioned elsewhere in the forums. I mailed the supplier and got an answer pretty fast:
Can you please check if the reboot cycle still appears when you switch off the unit, unplug the Ethernet cable and than switch on again with out Ethernet connection?
So this is how it's been running now rather smooth, since an hour or so and it doesn't get as hot as before. I'm connecting to it through the serial interface, played with the leds, found out that the clock drifted *slightly* away, It was 2018 when I first logged in.