You may need to edit grub to prevent the kernel from ever loading nouveau at boot. Run the following commands:
cp /etc/default/grub ~/grubbackup
sudo sed -i 's/GRUB_CMDLINE_LINUX_DEFAULT="/GRUB_CMDLINE_LINUX_DEFAULT="nouveau.blacklist=1 /g' /etc/default/grub
The file should look like this:
# If you change this file, run 'update-grub' afterwards to update
# For full documentation of the options in this file, see:
# info -f grub -n 'Simple configuration'
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="nouveau.blacklist=1 quiet splash"
# Uncomment to enable BadRAM filtering, modify to suit your needs
# This works with Linux (no patch required) and with any kernel that obtains
# the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...)
# Uncomment to disable graphical terminal (grub-pc only)
# The resolution used on graphical terminal
# note that you can use only modes which your graphic card supports via VBE
# you can see them in real GRUB with the command `vbeinfo'
# Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux
# Uncomment to disable generation of recovery mode menu entries
# Uncomment to get a beep at grub start
#GRUB_INIT_TUNE="480 440 1"
You can run the following command to verify the contents of the file to be safe before you reboot:
If you need to make changes, you can run the following command to edit the file:
sudo nano /etc/default/grub
Press CTR+o to save the file and then press CTRL+x to exit nano.
Also, don't forget to update grub after making changes: