Boot Ubuntu workstation into text mode

Boot without X

systemctl set-default multi-user.target
reboot

startx

Boot with X

systemctl set-default graphical.target
reboot

Display default target

systemctl get-default

Set VGA resolution

vi /etc/default/grub
#GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash vga=792"
update-grub
reboot

Display VGA modes

hwinfo --framebuffer
02: None 00.0: 11001 VESA Framebuffer
  [Created at bios.459]
  Unique ID: rdCR.EFc6IEIuFVE
  Hardware Class: framebuffer
  Model: "NVIDIA G80 Board - p355h00"
  Vendor: "NVIDIA Corporation"
  Device: "G80 Board - p355h00"
  SubVendor: "NVIDIA"
  SubDevice: 
  Revision: "Chip Rev"
  Memory Size: 14 MB
  Memory Range: 0xe1000000-0xe1dfffff (rw)
  Mode 0x0300: 640x400 (+640), 8 bits
  Mode 0x0301: 640x480 (+640), 8 bits
  Mode 0x0303: 800x600 (+800), 8 bits
  Mode 0x0305: 1024x768 (+1024), 8 bits
  Mode 0x030e: 320x200 (+640), 16 bits
  Mode 0x030f: 320x200 (+1280), 24 bits
  Mode 0x0311: 640x480 (+1280), 16 bits
  Mode 0x0312: 640x480 (+2560), 24 bits
  Mode 0x0314: 800x600 (+1600), 16 bits
  Mode 0x0315: 800x600 (+3200), 24 bits
  Mode 0x0317: 1024x768 (+2048), 16 bits
  Mode 0x0318: 1024x768 (+4096), 24 bits
  Mode 0x0330: 320x200 (+320), 8 bits
  Mode 0x0331: 320x400 (+320), 8 bits
  Mode 0x0332: 320x400 (+640), 16 bits
  Mode 0x0333: 320x400 (+1280), 24 bits
  Mode 0x0334: 320x240 (+320), 8 bits
  Mode 0x0335: 320x240 (+640), 16 bits
  Mode 0x0336: 320x240 (+1280), 24 bits
  Mode 0x033d: 640x400 (+1280), 16 bits
  Mode 0x033e: 640x400 (+2560), 24 bits
  Config Status: cfg=new, avail=yes, need=no, active=unknown

318 hex ≙ 792 dez

Install console mouse driver

apt-get install gpm
service gpm start