Grub external USB Hard-drive

[kellyw]

Hi,

I'm new to Linux. I've got a Toshiba Tecra laptop computer with Windows 7 installed on the internal Hard-drive.

I recently installed Ubuntu onto an external USB hard-drive. The installation was successful and I can now boot both Windows and Ubuntu via the newly installed GRUB boot loader.

Unfortunately, this only works if I have the USB external hard-drive connected. If it is disconnected then it give a device not found error (at boot time, prior to displaying a list of operating systems) and presents me with a grub rescue command prompt.

It's meant to be a portable laptop computer, so I don't want to have to carry the external hard-drive around with me all the time. I would like to be able to boot into Windows even if the USB external hard-drive is not connected.

Any suggestions?

Ideally, I'd also like to be able to boot up Ubuntu on this external USB hard-drive from other computers.

Cheers, Wayne.

[Vrekk]

Your problem is that you installed grub onto the Master Boot Record (MBR) of the wrong drive. In order to have the laptop boot without the external hard drive. (see ehow.com/how_4836283_repair-mbr-windows.html for more info on that, it has been ages since I have add to do that on windows lol)

If you want to be able to boot a computer from that usb hard drive, you will need to install grub to the MBR of the external hard drive. Do you this you will need to boot up a live cd, open a terminal as root a follow the instructions here: ubuntuforums.org/showthread.php?t=1195275 and that should get that installed into the right place, and get everything working

I'm sorry those are not working hyperlinks, I dont have 15 posts yet lol EDIT: And i'm 1 post short dang it!

[hatebreed]

I would do this. put in your windows cd and boot your system. then in the windows installation you should see a option to repair. hit this option and it will ask your your admin login. then type help and it will show all the commands you can use, I believe it's fixmbr and fixboot but check to make sure. this will load up the windows boot loader on your internal drive. then reboot to see if it took affect. after you verified that you can boot to windows reboot with your usb drive plugged in and boot to ubuntu. open up a terminal windows as root and type update-grub. this should find all the operating systems and allow you to boot to windows and ubuntu. reboot to see if all went well. post results.

[kellyw]

Thanks Vrekk!

All working now exactly as desired. I assumed the problem was something like that.

I used the Windows CD to enter the "repair computer" command prompt and used just the fixMBR option. It then was able to boot Windows without the external hard-drive connnected. I wasn't able to USB boot Ubuntu on the external hard-drive at that stage so I used the Ubuntu LiveCD to boot and reinstall grub using the root-directory option and pointed it at my external harddrive /dev/sdb. Upon rebooting via USB I was then presented with Grub men from which I can boot to Ubuntu or Windows. Success!

BTW, I didn't originally explicitly tell it to install grub onto any particular drive. I just used the Ubuntu LiveCD to install Ubuntu, followed the prompts and told it to install Ubuntu on a partition of my external hard drive - it automatically installed grub (somewhere).

BTW, I still don't completely understand the location of the grub components. Clearly part of the grub installation was installed onto my external USB hard-drive - but there must have been some grub configuration elsewhere as even with the external USB hard-drive disconnected it still presented me with a grub rescue command prompt (???)

Cheers, Wayne.