At boot prompt enter mc followed by one or more space separated options:

 Color            640x480     800x600      1024x768     1280x1024
   256    8 bit     769         771           773          775
 32000   15 bit     784         787           790          793
 65000   16 bit     785         788           791          794
 16.7M   24 bit     786         789           792          795

 vga=7xx                    7xx from table above
 xsetup                     Prompt user for Xvesa setup
 lang=en                    C only unless getlocale.tcz is installed
 kmap=us                    US only unless kmaps.tcz is installed
 text                       Textmode
 superuser                  Textmode as user root
 noicons                    Do not display icons
 noicons=ondemand           Do not display ondemand icons
 noswap                     Do not use swap partition
 nodhcp                     Skip the dhcp request at boot
 noutc                      BIOS is using localtime
 pause                      Pause at completion of boot messages