The general way that the Stage 1 handles errors is to print an error
string and then halt. Pressing CTRL-ALT-DEL will
The following is a comprehensive list of error messages for the Stage 1:
Hard Disk Error
The stage2 or stage1.5 is being read from a hard disk, and the attempt
to determine the size and geometry of the hard disk failed.
The stage2 or stage1.5 is being read from a floppy disk, and the attempt
to determine the size and geometry of the floppy disk failed. It's listed
as a separate error since the probe sequence is different than for hard
A disk read error happened while trying to read the stage2 or stage1.5.
The location of the stage2 or stage1.5 is not in the portion of the disk
supported directly by the BIOS read calls. This could occur because the
BIOS translated geometry has been changed by the user or the disk is
moved to another machine or controller after installation, or GRUB was
not installed using itself (if it was, the Stage 2 version of this error
would have been seen during that process and it would not have completed
The general way that the Stage 2 handles errors is to abort the
operation in question, print an error string, then (if possible) either
continue based on the fact that an error occurred or wait for the user to
deal with the error.
The following is a comprehensive list of error messages for the Stage 2
(error numbers for the Stage 1.5 are listed before the colon in each
1 : Filename must be either an absolute filename or blocklist
This error is returned if a file requested is not a regular file, but
something like a symbolic link, directory, or FIFO.
3 : Bad or corrupt data while decompressing file
This error is returned if the run-length decompression code gets an
internal error. This is usually from a corrupt file.
4 : Bad or incompatible header in compressed file
This error is returned if the file header for a supposedly compressed
file is bad.
5 : Partition table invalid or corrupt
This error is returned if the sanity checks on the integrity of the
partition table fail. This is a bad sign.
6 : Mismatched or corrupt version of stage1/stage2
This error is returned if the install command is pointed to incompatible
or corrupt versions of the stage1 or stage2. It can't detect corruption
in general, but this is a sanity check on the version numbers, which
should be correct.
7 : Loading below 1MB is not supported
This error is returned if the lowest address in a kernel is below the
1MB boundary. The Linux zImage format is a special case and can be
handled since it has a fixed loading address and maximum size.
8 : Kernel must be loaded before booting
This error is returned if GRUB is told to execute the boot sequence
without having a kernel to start.
9 : Unknown boot failure
This error is returned if the boot attempt did not succeed for reasons
which are unknown.
10 : Unsupported Multiboot features requested
This error is returned when the Multiboot features word in the Multiboot
header requires a feature that is not recognized. The point of this is
that the kernel requires special handling which GRUB is likely unable to
Some of the filesystem reading code in GRUB has limits on the length of
the files it can read. This error is returned when the user runs into
such a limit.
15 : File not found
This error is returned if the specified file name cannot be found, but
everything else (like the disk/partition info) is OK.
16 : Inconsistent filesystem structure
This error is returned by the filesystem code to denote an internal
error caused by the sanity checks of the filesystem structure on disk
not matching what it expects. This is usually caused by a corrupt
filesystem or bugs in the code handling it in GRUB.
17 : Cannot mount selected partition
This error is returned if the partition requested exists, but the
filesystem type cannot be recognized by GRUB.
18 : Selected cylinder exceeds maximum 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).
19 : Linux kernel must be loaded before initrd
This error is returned if the initrd command is used before loading a
Linux kernel. Similar to the above error, it only makes sense in that
20 : Multiboot kernel must be loaded before modules
This error is returned if the module load command is used before loading
a Multiboot kernel. It only makes sense in this case anyway, as GRUB has
no idea how to communicate the presence of location of such modules to a
21 : Selected disk does not exist
This error is returned if the device part of a device- or full file name
refers to a disk or BIOS device that is not present or not recognized by
the BIOS in the system.
22 : No such partition
This error is returned if a partition is requested in the device part of
a device- or full file name which isn't on the selected disk.
23 : Error while parsing number
This error is returned if GRUB was expecting to read a number and
encountered bad data.
24 : Attempt to access block outside partition
This error is returned if a linear block address is outside of the disk
partition. This generally happens because of a corrupt filesystem on the
disk or a bug in the code handling it in GRUB (it's a great debugging
25 : Disk read error
This error is returned if there is a disk read error when trying to
probe or read data from a particular disk.
26 : Too many symbolic links
This error is returned if the link count is beyond the maximum
(currently 5), possibly the symbolic links are looped.
27 : Unrecognized command
This error is returned if an unrecognized command is entered into the
command-line or in a boot sequence section of a configuration file and
that entry is selected.
28 : Selected item cannot fit into memory
This error is returned if a kernel, module, or raw file load command is
either trying to load its data such that it won't fit into memory or it
is simply too big.
29 : Disk write error
This error is returned if there is a disk write error when trying to
write to a particular disk. This would generally only occur during an
install of set active partition command.
30 : Invalid argument
This error is returned if an argument specified to a command is invalid.
31 : File is not sector aligned
This error may occur only when you access a ReiserFS partition by
block-lists (e.g. the command install). In this case, you
should mount the partition with the `-o notail' option.
32 : Must be authenticated
This error is returned if you try to run a locked entry. You should
enter a correct password before running such an entry.
33 : Serial device not configured
This error is returned if you try to change your terminal to a serial
one before initializing any serial device.
34 : No spare sectors on the disk
This error is returned if a disk doesn't have enough spare space. This
happens when you try to embed Stage 1.5 into the unused sectors after
the MBR, but the first partition starts right after the MBR or they are
used by EZ-BIOS.