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I use Ubuntu 12.04 LTS in my Mac Mini with OS X Lion.

Unfortunately I have set the timeout as -1 in the /boot/grub/grub.cfg file, and Ubuntu displays a menu screen to select an OS to boot (Ubuntu or Mac) during Grub session.

But another unfortunate thing, my keyboard does not work during the GRUB session.

What can I do?

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up vote 2 down vote accepted

Use a Live-CD/USB, and increase the timeout value to a positive number.

It may also be possible to mount your boot/root partition from OS X and make the change there.

For future reference, changes in /boot/grub/grub.cfg do not persist; you should edit /etc/grub/default instead.

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Thanks very much, I have done this with my live USB. But, I wonder how the Linux system allow this, without asking for any password to do this? It seems anyone can boot my machine using a USB thumb drive, and do disaster to my system! Isn't it a security hole in the Linux system? – DUKE May 31 '12 at 5:44
Anyone with physical access to plug in the USB can simply wipe the hard disk or remove the hard disk or just "steal" your laptop/desktop! Controlled physical access/security is the first security measure :) – izx May 31 '12 at 7:11

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