macOS 10.14.6 on MacPro3,1

Thing should have gone a bit smoother if only I took a bit more time preparing.

Since last time, I have changed my file system to APFS which allows normal software update via Apple.

As such I just needed to download and restart to install.  Or so I thought.

I was basically taking a chance as I didn't put back the stock GPU.

So when it reboot, nothing kind of happened.  I tried holding Alt, or Command R to get under the hood.  I tried a few times.  I am using bluetooth keyboard and touchpad so they can be a bit iffy when doing the bootup and holding down keys kind of operation.  But apparently it can be done.  I suppose the bluetooth connection is pretty low level and is connected right away without the OS fully loaded so you can work on it right away.

Since I couldn't boot up so actually got my old macOS USB drive and boot with Alt down and boot to base macOS.  I used Time Machine to go back to 10.14.5.

I got everything running and I made sure I removed the non native GPU and put the stock GPU back before I started my download, install and reboot route.

It seems like I need to remove the USB drive, or I am not sure as I thought unless you hold down Alt otherwise it doesn't matter.

In any event I was able to boot back into the user login screen.  And the patch program automatically asked to update the patches.  Then reboot.

After everything works like I am sure it's the latest 10.14.6, then I powered down, removed the stock GPU card and put back the newer more powerful but not natively supported GPU.

It was on my third trial that everything worked.