It should not matter since video/graphic part of system should not be started.
Anyway an easy way to boot to maintenance mode:
When you get to grub2 menu while on the “normal” boot line press ‘e’ for edit. Navigate down to the Linux line, press ‘end’ key to go to end of line. Type a space and ‘3’. (For run level 3.) Then press F-10 to boot.
Let us know if that works and the other stuff needs to be investigated but I am not sure how to do that.