How to speedup the boot of opensuse studio and show boot messages

I want to create an image that will:

show as much info during boot as possible (for coarse profiling of the boot steps)
boot as fast as possible to a shell prompt

Note: the bootloader is grub2, but I couldn't create the corrsponding tag, so I used the closest available: "grub".

Solution

This is what I came up with, trying to use the interface provided by Suse Studio. In the script to be run at every boot of the appliance:

# read in some variables
. /studio/profile

if [ -f /etc/init.d/suse_studio_firstboot ]
then
  # Put commands to be run on the first boot of your appliance here
  echo "Running SUSE Studio first boot script..."

  #remove grub2 splash screen and boot delays
  sed -i "s/GRUB_HIDDEN_TIMEOUT_QUIET=true/GRUB_HIDDEN_TIMEOUT_QUIET=false/" /etc/default/grub
  sed -i "s/GRUB_TIMEOUT=.*/GRUB_TIMEOUT=0/" /etc/default/grub
  sed -i "s/quiet splash=silent//" /etc/default/grub
  sed -i "s/gfxterm/console/" /etc/default/grub
  sed -i "s/GRUB_THEME.*//" /etc/default/grub
  sed -i "s/GRUB_BACKGROUND.*//" /etc/default/grub
  /usr/sbin/grub2-mkconfig -o /boot/grub2/grub.cfg
  rm -f /etc/init.d/suse_studio_firstboot
  sync
  /sbin/reboot
fi

Example can be found here: https://susestudio.com/a/AMSHUG/pc-flasher-32-bit-mbr-efi