@jhowarth That was just my speculation, not a tested solution (and it should be tested by more than a handful of people).
[doublepost=1503754037][/doublepost]On top of that, even if we can replicate that every single time, it's not a viable solution
in my opinion. It's just not reasonable to expect people to jump through all those hoops to get it to work. We need a better, solid solution. Majority of folks are not really tech-savvy and the only reason they can run new versions of macOS on their unsupported machines is because of those other "crazy" folks here who not only figure out
how to do it, but they make simple to use tools, so
everyone can do it, regardless of their skill level and knowledge.
@roziek
I agree with you, that upgrading over older systems may have preserved authentication for iMessage, face time, and iCloud. That's why I stated explicitly that I never did perform a "clean install," just upgraded over older systems.
One way to call your bet, and prove a point, as you mentioned above, is for brave soul to erase completely their High Sierra installation, in process reformatting APFS back to HFS+, reinstall last system where those services were functional, via dosdude1's patcher, test to make sure services still work after each upgrade, and then, as last step apply patch to convert to APFS. On successful conversion, test if iCloud, iMessage and Face Time remain fully functional.
In regard to "erasing containers." Perhaps it is a matter of semantics, but I did not erase any containers in my rescue bid to boot my laptop. I erased *contents" of an HFS+ (helper) partition, and then merged that empty partition with the AFPS partition (container), in non destructive manner. In essence, I reversed dosdude1's partitioning schema. This gave the patcher a clean slate to resize AFPS container and allow formation of new helper partition. Dosdude1 has an explanation of his schema few posts above.
I tested the iMessage: my text was received and acknowledged by family member; two way communication.
iCloud test: I created a calendar event on my iPhone, while laptop was shutdown. When I booted laptop, the new event was present in the iCal on the laptop. I also received emails through my iCloud account.
Face Time: I can launch Face Time with camera activated and all contacts listed in sidebar. I did not have a chance to engage in face-time conversation, but I will try to do so later.
Luigi222 had an interesting idea, to call Apple support and ask why there are problems accessing iServices (?) Perhaps they could help reset the connection server (?) Alternatively, consider sequential system installation, as noted above, to solve the riddle. At some point sequential reinstallation process, might be less of a headache than not having the services in question (?)