Please don't write so "compact" - think of the people to read it
I first had one idea, but it was not that, but it's worth mentioning here.
If you put the first stage of grub (under Advanced in the last screen of the install) on another disk than you install on you have to block gfx - meaning that you comment out like this
or you'll get an error message that you can bypass.
But it was not this, so I don't go into it in detail.
Please tell us what 38% is, what have you passed by and what is it to do now - else we have to start an install to find out.....