... and it did not work. I did get the PAC-Man boot animation, but it never went further. Yes, I know, first time can be very long, but no that long.
I am slowly learning. While trying to re-install a stock ROM, twrp was removed (I guess this is to be expected) so that I had to use again AIO Toolkit. That's when I discovered that it had an option to switch my device to new bootloader. This was the final solution: I was able to install PAC-Man without converting it, and of course it worked immediately.
I am not quite happy with PAC-Rom, though, it is laggy, and it still has the same CM bug I am trying to get rid of, but that is another story.