Question How can I get GRUB to take a different OS as the default one ? All the usual methods as explained on the ubuntu site haven't worked. The only thing I haven't tried yet is GRUB Customizer out of fear to break something.

The context I have multiple operating systems, among them two Ubuntu 11.10 distros. Two distinguish them, lets call them OS A and B. I first installed A, spent a lot of time setting it up the way I like it to be, an then I installed B as an OS with which I can fool around a bit. Until now, GRUB worked fine. The problem was, after installing B GRUB is now set to start B as default and I can't change it. I tried different things ( like editing some files to change the start order and then updated GRUB via sudo update-grub), or using Startup manager(so the proposed answers askubuntu gives me for this question don' count), but nothing helped. Generally, I can't change anything in GRUB, not even other things like how long the screen with the OSes is being displayed (I wanted it to be as short as possible, but it's still at 10 seconds). All attempts to do this were done from OS A. I haven't tried GRUB Customizer because there are a lot more entries shown there that at the boot process, so I don't know whats happening with that. I also would like to remove some entries from the GRUB menu (like different kernel version of the same OS), but in GRUB Customizer I'm afraid to tick the wrong things off.

Here is my etc/default/grub file:

# If you change this file, run 'update-grub' afterwards to update

# /boot/grub/grub.cfg.

# For full documentation of the options in this file, see:

#   info -f grub -n 'Simple configuration'



GRUB_DEFAULT=14

#GRUB_HIDDEN_TIMEOUT=0

GRUB_HIDDEN_TIMEOUT_QUIET=true

GRUB_TIMEOUT=1

GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

GRUB_CMDLINE_LINUX=""



# 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 ...)

#GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef"



# Uncomment to disable graphical terminal (grub-pc only)

#GRUB_TERMINAL=console



# 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'

#GRUB_GFXMODE=640x480



# Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux

#GRUB_DISABLE_LINUX_UUID=true



# Uncomment to disable generation of recovery mode menu entries

#GRUB_DISABLE_RECOVERY="true"



# Uncomment to get a beep at grub start

                #GRUB_INIT_TUNE="480 440 1"