First of all - thanks, dosdude1, for your amazing work! I've been following the thread as a reader right from the start.
I'm currently trying to update a MacBook Pro 5,5 (mid 2009, 2,53 GHz C2D, 8 GB RAM, 512 GB SSD) from El Capitan 10.11.6 to macOS Sierra 10.12 using your latest version of the patcher tool. I have successfully downloaded Sierra using the tool and created the bootable usb drive.
However, when booting from the usb drive, I cannot select my El-Capitan-partition as an installation target. It doesn't show up on the selection screen. When booted from the usb drive, disk utility shows the internal drive as "unformatted" (which it is not; I can easily reboot and boot off of it). When booted in El Capitan, disk utility properly identifies the drive as having a GUID partition map and only one partition (Macintosh HD as a "Logical Volume Mac OS X Extended").
Any idea what's going on? The drive is encrypted with file vault, may that be the problem? (I thought that was a problem of previous Sierra-versions and fixed in the final release?)