GRUB Error Reference

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The objective of this error collection is to list the GRUB problems and errors people can be facing. All these solutions have been acquired through the cooperation of many users of the Gentoo Forums.

Starting notes


Many thanks to Earthwings, penetrode, loyaltonone, pilla, airhead, nephros, yamakawa and all the others for the suggestions on the original thread.

Disclaimer warning

The examples provided are just examples. Be sure to change partition numbers and the like according to your systems specs. Follow the solutions provided by this document at your own risk.

Grub loading, please wait...


GRUB loading stage 1.5
GRUB loading, please wait...

After this message, the system stops. If you attempt to boot the system using a GRUB floppy, the problem disappears.


According to The_Bell you could change the boot order in your BIOS.

Tell your BIOS to not boot from your floppy first.

[1] took hard disks off the system one-by-one until found out the problem was caused by the SiI3512A SATA RAID-controller.

penetrode wrote that this may also be due to bad CFLAGS settings. Although the current GRUB ebuild filters out-fstack-protector, it can't hurt to recompile GRUB with clean CFLAGS if nothing else helps.

root #CFLAGS="-O2 -march=i686 -fomit-frame-pointer -pipe" emerge grub:0 --ask

I had this problem on a dell r320 server, caused by having serial and terminal options in grub,conf, problem disappeared after removing those options.

FILE grub.confoptions to remove
#serial --unit=1 --speed=19200  
#terminal --timeout=10 serial

Grub Error 12


12 : Invalid device requested.

This error is returned if the device strings syntax is correct but other than that, an error occurred that isn't defined by any other error.


When you installed GRUB in your boot record using the interactive commands, did you execute the two lines below in the GRUB prompt?

grub>root (hd0,0)
grub>setup (hd0)

(hd0,0) must be replaced with your boot partition and (hd0) with the HDD you have chosen. Remember that (hd0) will install the bootloader in the Master Boot Record of the first hard disk, the primary master.

Grub Error 15


This error can occur in two different stages of the GRUB configuration, either during the initial configuration (installing GRUB in the master boot record) or after booting the system and attempting to launch Linux (or any other entry).

  • Initial Configuration:
grub>root (hd0,0)
 Filesystem type is xfs, partition type 0x83
grub>setup (hd0)
 Checking if "/boot/grub/stage1" exists... no
 Checking if "/grub/stage1" exists... no

Error 15: File not found
  • Booting an Entry:
Booting 'gentoo Linux'
root (hd0,0)
Filesystem type is ext2fs, partition type 0x83
kernel (hd0,0)/boot/kernel-2.4.20 root=/dev/sda3 vga=792
Error 15: File not found
Press any key to continue...

Solution - Initial Configuration

This error is returned if the specified file name cannot be found, but everything else (like the disk/partition info) is OK.

Frequently, the error notes a missing kernel image file. Make sure that the file it is referring to exists on your boot partition.

To find out the exact name of your kernel, boot from the installation cd, mount your root and (if applicable) boot partition. Next, chroot into your Gentoo system and do a listing of the available files to see what kernel images you have available:

root #cd /boot
root #ls

This will list all the kernels that you've got on your boot partition. If your kernel is missing make sure that you compiled a kernel (using genkernel or manually):

root #cd /usr/src/linux/
root #make menuconfig
root #make

And that you copied it to your boot partition:

root #cp /usr/src/linux/arch/i386/boot/bzImage /boot

Verify that the name of the kernel is exactly the same as the one mentioned in your grub.conf file. Also make sure that the kernel line in your grub.conf file is referring to that partition (either explicitly or implicitly).

Another reported mistake is to have the BIOS ignore the disk on which the kernel or GRUB stages reside. Also, the partition on which GRUB stores its stages should not use a software RAID-5 (or other striping technology) configuration.

Solution - Booting an Entry

First, verify that the root and setup lines you have used are correct.

If you are certain they are valid, then you might be using a flawed GRUB version (0.93.20031222). Upgrade your Portage tree or mask this version of GRUB:

root #echo "=sys-boot/grub-0.93.20031222" >> /etc/portage/package.mask
root #emerge --ask grub:0

You could also try to use the grub-install script as is recommended by the GRUB authors. The --root-directory option is needed if you are using a separate boot partition, otherwise you should leave it out.

root #grub-install --root-directory=/boot /dev/sda

When all this fails, your boot partition may be corrupt. Check the partition for errors:

root #fsck -y /dev/sda1

Grub Error 17


root (hd0,0)
filesystem type unknown partition type 0x7
Error 17 : Cannot mount selected partition


This error is returned if the partition requested exists, but the filesystem type cannot be recognized by GRUB.

Be sure to check your root(x,y) settings in your grub.conf.

Also, if you are trying to boot Windows, make sure that your grub.conf file has the root (hdX,Y) (or rootnoverify (hdX,Y) ) and chainloader (hdX,Y)+1 in it.

Grub Error 18


kernel (hd1,4)/bzImage root=/dev/sdb7
Error 18: Selected cylinder exceeds max supported by BIOS


This error is returned when a read is attempted at a linear block address beyond the end of the BIOS translated area. This generally happens if your disk is larger than the BIOS can handle (512MB for (E)IDE disks on older machines or larger than 8GB in general).

Try an update for your BIOS and/or move your boot partition to the front (or at least into the appropriate range).





According to airhead this can be caused by having your BIOS detect your disks automatically. Try to set your BIOS entry to User Type HDD.

Another possibility is that you had Grub installed on your MBR and tried reinstalling it (for instance due to hard disk changes) but used the wrong setup and root commands.

Probing Devices to Guess BIOS Drives. This May Take a Long Time.


While trying to install GRUB, it hangs after displaying the following line:

root #grub
Probing devices to guess BIOS drives. This may take a long time.


One reported cause was an exotic configuration of disk devices, like ultra/non-ultra DMA disks on one cable.

When Installing Grub, It Just Hangs


When installing GRUB, it hangs:

root #grub

At this stage, the installation stops.


If you haven't got a floppy drive, have you used the --no-floppy switch?

root #grub --no-floppy

Uncompressing Linux... Ok, booting the kernel.


The system hangs after displaying the following line:

Uncompressing Linux... Ok, booting the kernel.


Strictly speaking, this is no GRUB error. One possible cause is that ACPI is not working correctly but is enabled in the kernel. Try to disable it in your BIOS or in your kernel.

Grub Just Shows a Grub Prompt


When booting the system, you receive a GRUB prompt instead of a list of entries you have defined in your grub.conf file.


Mount your boot partition and verify if the grub/grub.conf file exists.

root #mount /dev/sda1 /mnt/gentoo/boot
root #cat /mnt/gentoo/boot/grub/grub.conf

Also make sure that the menu.lst symbolic link exists:

root #ls -l /mnt/gentoo/boot/grub/menu.lst
lrwxrwxrwx  1 root root 9 Mar  7 14:00 /mnt/gentoo/boot/grub/menu.lst -> grub.conf

If not, recreate the symbolic link:

root #cd /mnt/gentoo/boot/grub
root #ln -snf grub.conf menu.lst

If this is the case, reinstall GRUB:

(chroot) #grub-install --root-directory=/boot /dev/sda

Could Not Find Device For /boot/boot: Not Found Or Not a Block Device


When running grub-install during the GRUB installation, you receive the following error:

root #grub-install --root-directory=/boot /dev/sda
Could not find device for /boot/boot: not found or not a block device


Check that you didn't forget the following:

root #grep -v rootfs /proc/mounts > /etc/mtab

The System Reboots After Hitting Return At The Grub Menu


After hitting Return at the Grub menu during the system boot, the system reboots.


Try disabling framebuffer support in your kernel. If this does not help, disable APM and ACPI.

After Hitting Return At The Grub Menu, The Screen Blanks Out


After hitting Return at the Grub menu during system boot, the screen blanks out, but the system is responsive (for instance, your numlock led is switchable).


Turn off framebuffer (typically remove vga=XYZ from your grub.conf ) and check the processor architecture in your kernel config.

Missing Grub Image


When booting the system, you do not see that spiffy Gentoo splash screen.


First of all check if the splash creen file you are referring to in your grub.conf really exists. If that is the case, go and check the GRUB ebuild. Maybe the patch for the splash image is commented out in the version that you are using.

Failing To Boot Windows From a Second Hard Drive


After selecting the Windows entry, the system refuses to boot without any clear reason as to why.


cyrillic informed us that you can "map" your disks in a different order by changing your grub.conf 's Windows entry like so:

FILE grub.confMapping disks
title Windows XP
  map (hd0) (hd1)
  map (hd1) (hd0)
  chainloader (hd1,0)+1

Grub segfaults when trying to install


The situation described below is only relevant for grub-0.95.x at the moment of installing GRUB at the boot sector.

grub>root (hd0,0)
grub>setup (hd0)
Segmentation fault


This is a known bug related to this problem and has been fixed in grub-0.96. It is also known that grub-0.94-r1 and grub-0.94-r2 should work correctly. If that fails too, you can try to emerge grub-static which is currently stable on amd64 and unstable on x86 (~x86). Check out bug #79378 for additional information.

This article is based on a document formerly found on our main website
The following people have contributed to the original document: Hartwig Brandl, Ioannis Aslanidis, Sven Vermeulen
They are listed here as the Wiki history does not provide for any attribution. If you edit the Wiki article, please do not add yourself here; your contributions are recorded on the history page.