Chosen Solution
MD102LL/A 2.9GHz 8 GB RAM 500GB SSHD 13" Mid 2012 This is a strange one for me. It works just great with Mavericks 10.9. I have tried it with several drives now and anything El Capitan and over causes a kernel panic. used different drives both internal and external with know good systems. Also downloaded new systems but I soon as I get to El Capitan it fails. Yes I tried High Sierra. This machine was not known for a GPU disorder but that is what I suspect (something in the dual graphics software). Has anyone like @danj seen this? UPDATE 3/22 I started all over, new drive new cable. Downloaded new clean systems and installed Mountain Lion, Mavericks then Yosemite. Everything worked fine till El Capitan. Then I got the kernel panic screen and a reboot loop. No way to get to Activity our Terminal. UPDATE 4/3/18 I contacted Apple support on this issue. After a couple of hours and call backs, I have managed to get Apple to better efforts to resolve this. I have uploaded the log to them and it is now going to the specialists for help. They told me they would get back to me within the week. I would not accept the answer of “send it in for a $357 depot repair” as it is a system software issue. UPDATE 1/14/19 The problem turned out to be Apples’ installation software imposing APFS formatting on 3rd party SSHD drives. I have found that for it to work on theses drives, you cannot just update, you have go in and reformat the drive APFS, then install a system, then migrate your old data.
I tried completely different RAM brands. Tried just one in each slot. It is not the RAM. @danj it is BootROMVersion: MBP91.00D3.B15 When I download the update it tells me it only works on 10.9.5 The SMC update tells me “the software is not supported on your system. After Googling that, this may be the problem fix: https://support.apple.com/en-us/HT201518
Could it be a case of bad RAM? Have you tested the memory? The difference is a shift from 32-bit to 64-bit in core apps, services, and KEXTs.
