Hi guys, I recently installed Linux mint 15 cinnamon 32-bit on my 40GB external hard drive. I used an 8GB flash as a live CD, and install onto the external. the installation works just fine, but it will only boot when the 8Gb is also present at boot. from the error messages I think it is looking to boot from sdc1 at boot, but if the 8GB isn't plugged in the externals /dev/ path changes and therefore grub looks in the wrong place to boot. is there any way to edit the grub config file to make it look at the Linux installation even if other devices are removed or inserted?
side note: this problem is because of the something else partition thing during installation. I installed the boot loader on the same external hard drive, which is correct. if there is any info that can help just ask me for it..
thanks in advance

you can probably change the boot order in your bios to make it map the flash drive as later than the install partition.

No it is nothing to do with the bios whatsoever, it is only to do with grub. it should be noted that I also have a mint installation on the internal hard drive

With flash drive connected, mount all partitions on sda, then run that should find your other mint partition, Reboot into other mint, unmount & remove flash & issue command

1 members found this post helpful.

Thanks for the reply, let me describe what gets mounted at /dev/
sda is the internal hard drive of the PC
sdb is the 8GB usb "live CD" that i used to install LM15 on my external
sdc is my 40GB external hard drive that has LM15 on it

can I not just update grub and execute on the external?
I want the external to be able to boot without the necessity of my live CD usb being plugged in.
ie. even in a computer that has no internal hard drives

No

What I believe you want is to have the bootloader on the external drive

if sda is internal then leave the flash connected but try

2) Now bios becomes important from your last request
as not all bios allow usb boots

modern ones do
but if you have an old one,
you can download plop as a cd which will give you usb drivers
or download UBCD which contains plop

YMMV

but before doing so, check that external has grub2 files on it pls

1 members found this post helpful.

no worries about old motherboard, it supports usb boot, i have grub2 files located in:
/boot/grub
/etc/grub.d
/etc/default/grub

the bootloader was installed to sdc TOSHIBA 40GB at time of installation. that is my external HD

Let's see some hard data - boot the external, go get and run bootinfoscript (may even be installed in Mint by default).
Post the RESULTS.txt it generates.

You may have told the installer to install grub to sdc but installers tend to get confused at times and incorrectly install grub. That is why LQ has so many threads about grub not booting correctly after instalation. If you boot your external Mint drive, do fdisk -l to get the dev number of the external drive then do grub-install /dev/<dev number of external mint drive> should fix grub.

technically grub is installed to the correct place, the external hard drive which was sdc1 at the time, and if the 8GB is not present at boot,then i presume that it looks for sdc1 which is actually then sdb1.

redacted - my apologies for being impatient.

here is the results file

Attached Files

RESULTS.txt (16.9 KB, 25 views)

Hence my request for hard data - I see Mint is no longer on the internal disk.

That looks pretty lame - Ubuntu (hence Mint) disavowed the use of /dev device addresses years ago. I don't use Ubuntu (I have a Mint somewhere, so I'll go check), but I find that grub.cfg odd. The hardcoded "root=/dev/hdc1" (on the "linux" line) is the reason you need the USB in place to successfully boot the external.
Were you to change it to "root=UUID=ff5e1218-a92c-4e50-ad54-a377b057d91f", you'd probably be o.k. - but you shouldn't have to. Raise a bug against Mint.

Any particular reason you are using ext2 ?.

1 members found this post helpful.

well the results file posted is from another computer- now before you tell me that it makes a big difference, this is the school's computer lab, in which all the pcs are identical- the internal mint is on the pc i use. but that isnt the point.
i use ext2 because it was the easiest option, and i do not think the installer had an option to make a ext3 filesystem.
so how would i go about fixing the need for the 8GB in grub.cfg?

You probably need to rerun the grub-install manually. Just because all the grub bits exist in /boot/grub doesn't mean that it's installed on the MBR or installed correctly on the MBR of the drive you're intending to boot grub from. And be sure to use UUIDs instead of /dev names. Double check the grub.cfg after update-grub to make sure it's right.

1 members found this post helpful.