Questions about these errors are asked so often on Usenet that we include them here as a public service. This summary is excerpted from Werner Almsberger's LILO User Documentation, available at http://metalab.unc.edu/pub/Linux/system/boot/lilo/lilo-u-21.ps.gz.
When LILO loads itself, it displays the word ``LILO''. Each letter is
printed before or after performing some specific action. If LILO fails at
some point, the letters printed so far can be used to identify the problem.
No part of LILO has been loaded. LILO either isn't installed or the partition on which its boot sector is located isn't active.
The first stage boot loader has been loaded and started, but it can't load the second stage boot loader. The two-digit error codes indicate the type of problem. (See also section ``Disk error codes''.) This condition usually indicates a media failure or a geometry mismatch (e.g. bad disk parameters)
The first stage boot loader was able to load the second stage boot loader, but has failed to execute it. This can either be caused by a geometry mismatch or by moving /boot/boot.b without running the map installer.
The second stage boot loader has been started, but it can't load the descriptor table from the map file. This is typically caused by a media failure or by a geometry mismatch.
The second stage boot loader has been loaded at an incorrect address. This is typically caused by a subtle geometry mismatch or by moving /boot/boot.b without running the map installer.
The descriptor table is corrupt. This can either be caused by a geometry mismatch or by moving /boot/map without running the map installer.
All parts of LILO have been successfully loaded.
If the BIOS signals an error when LILO is trying to load a boot image, the
respective error code is displayed. These codes range from 0x00 through
0xbb. See the LILO User Guide for an explanation of these.