Logic board which can boot via USB, but not via internal SATA

Thank you for your input. Given your info I will just put the logic board into one of my 2009 17” machines and see what happens with a few of the internal HDDs I have at hand. Perhaps the seller of the board just shot himself in the foot by using a corrupt HDD or, as you said attempted to run Sierra on a 2009 machine. I will let you know once I see what happens.

And Mayer, I will dig through my pics and see if I have some of my panels and post them.If not, I will take some, and also take some pics of the battery bank and inverter system while I am at it. Might even break down and clean my battery terminals for the occasion…they need attention every few month…I was looking at wind power today as well, since I have a grey zone right now, not much sun, and not enough water in the creek…Besides, the government here believes that it owns all surface water and wants me to ask them for permission and charge me for “their”water…. the usual insanity we have come expect from what goes for govmt in North America….imho.

@jurgenkoppen There is no problem with Sierra, just above that creates does the APFS mess. I understand your concern about government overreach. Some of this regulation got rescinded today in the USA. If they charge you for the water, send them a bill when they don't provide enough, He who controls the spice.......