scrambled screen

Just installed 13.1 and even with the advanced failsafe second line in use, get to end of sequence, but with screen that scrambled -- and there are no options for altering boot process like in earlier versions. What I noticed is that at beginning of install, and for the first time ever regarding the install screen itself, the screen was cut short, so had to go back and use less dense screen line option instead of the default. That put things right, but now I'm wondering if need to avoid the screen default also on the boot process -- but there is no option to change it.
Any suggestions welcomed.