Ubuntu – How to change default boot kernel if I set it wrong to memtest?

bootgrub2

Possible Duplicate:
How do I change the grub boot order?

O.K., I follow How to set default boot kernel in Ubuntu / Grub? and make a mistake. I didn't count the entry from 0… I want to set default boot kernel as Linux 3.2.17-chipsee,
count it (begin from 1) from the top, and I get 3. It seems grub will skip those menuentry with recovery mode, and select memtest as default boot option. Now when I boot the machine, it cannot skip memtest. After memtest is done, the machine still reboot into memtest. How can I fix this mistake? I try to boot Ubuntu from the cd-rom, and edit /etc/default/grub file on the disk. But it told me that's read-only… Thanks.

$ grep menuentry /boot/grub/grub.cfg
menuentry 'Ubuntu, with Linux 3.2.17experimental' --class ubuntu --class gnu-linux --class gnu --class os {
menuentry 'Ubuntu, with Linux 3.2.17experimental (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os {
menuentry 'Ubuntu, with Linux 3.2.17-chipsee' --class ubuntu --class gnu-linux --class gnu --class os {
menuentry 'Ubuntu, with Linux 3.2.17-chipsee (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os {
menuentry 'Ubuntu, with Linux 3.2.0-23-generic' --class ubuntu --class gnu-linux --class gnu --class os {
menuentry 'Ubuntu, with Linux 3.2.0-23-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os {
menuentry "Memory test (memtest86+)" {
menuentry "Memory test (memtest86+, serial console 115200)" {

Best Answer

  • From the https://help.ubuntu.com/community/Grub2

    You can change which kernel grub boots to during the computers start-up.

    As the computer starts up.

    Hold down SHIFT to display the menu during boot. In certain cases, pressing the ESC key may also display the menu.

    enter image description here

    You should now see the the grub menu. Use the arrow keys to navigate to the correct kernal to boot. Then follow instructions in the above post.

    Then follow the instructions in this post to fix the menu entry.

    Or try the ubuntu community documentation here. https://help.ubuntu.com/community/Grub2/Setup#Configuring_GRUB_2

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