git checkout `git rev-list -n 1 --before="2015-09-09 11:11" master`
to return to earlier dates, is that correct?
I can't reproduce a state where the things I found faulty now have worked, so it's entirely possible I didn't run into them then, and my memory is acting up, e.g. I've installed DOS a different way and reset with Shift-F3 anyway or I had trouble installing Sinix 1.2 and just left it at that.
The Sinix 1.0 is working all the way back since the harddisk emulation became fully functional if you set the MMU correctly.
Even if you set the MMU to 1.2, Sinix 1.2 installs but then throws NMIs and ends up in the monitor.
DOS fails to reboot after e.g. changing a partition with FDISK.