So if your diagnosis is right, it seems there is a serious hardware error.
I was hoping there wasn't (like some loose cable on the PSU or something).
In that case I suppose sending it in for repair and hoping for the best is the smartest move. 

Putting it on the side actually did work for me before. I read about this somewhere in this forum. Tried it again today, this time without success.

The nature of my project does not allow for constant electricity supply. I do have free electricity from time to time, but at other times its rather expensive. The miner is supposed to be installed inside the tower of a windmill. 

Thats why I am coding a control software that will tell my miner what to do, based on the current price of electricity (if selling the energy is more profitable I won't mine). By my calculations it will be able to run profitable about 70% of the time though, which should result in profit long term.


Regarding your tips:
1. time saving is not important right now. This is a research project and I need a functioning S17+ to do proper research. Profitability is not relevant (yet).
2. I am running BraiinsOS on all our S9s (12 in total). It has not released yet for S17+ (but will be this year). I am planning to use it for this S17+

I have also tried Awesome Miner Firmware. It has the same issues (missing hashchain).
Setting a low power profile did not resolve this.