Debian Jessie grub serial console problem


I installed Debian Jessie over serial console successfully.

But when I try to boot my system, it gives following error on grub screen:

text is deprecated. Use set gfxpayload=vga=off before linux command instead.
error: unrecognized number

It seems that correct serial parameters already added linux commandline arguments (console=ttyS0,115200n8) but I couldn’t pass above error.


First of all, you have too boot rescue or live mode to mount your root partition.

You can boot into rescue mode over serial console with following boot parameters of Debian Jessie installation (press H to go Help mode first):

rescue vga=off console=ttyS0,115200n8

Follow the steps and when rescue mode setup finished, select “Execute shell” option. It asks what is your root device and if it can find a root filesystem on it, a shell will be prepared for you within a chrooted environment.

This is the place where your actual root filesystem was. Open /etc/default/grub and make sure that GRUB_CMDLINE_LINUX doesn’t have options like that: vga=off

If such an option exists (yes, it sounds seem strange because we already booted with this parameter, but grub has some problems with), remove vga=off part from it and run following command:

# update-grub

After reboot, you’ll see a normal boot process.