Screen resolution while booting and on CLI

Hello, I have a problem with the screen resolution while booting the PC and afterwards. Part of the font is cut up at the left hand and upper side of the screen before booting into Arch Linux. And in Arch Linux itself (when the log in screen appears) the screen resolution is way too high, everything is located at the upper left corner of the screen. I don't use a graphical user interface so I can't use randr or anything else, I am on a Linux terminal. Is there a way to adjust screen resolution in BIOS? And is there a way to adjust screen resolution in a Linux terminal without xorg? I tried putting "vga=ask" into "GRUB_CMDLINE_LINUX_DEFAULT", but that didn't do anything. Regards Björn