live-build uses syslinux and some of its derivatives (depending on the image type) as bootloaders by default. You can easily customize them in a number of ways that range from providing a full theme to changing the boot timeout or simply adding a personalized splash image. Some of the following examples of customization make use of different methods, like includes or hooks.
If you want to use a full theme you can specify the --syslinux-theme option (see man lb_config). live-build will then retrieve the theme from the mirror and install it.
Imagine that you want to build a progress client but you prefer to include the server's theme because you want to have the help menu. Then you would launch lb config as follows:
$ lb config --mode progress --syslinux-theme progress-server
You can also create your own theme or modify an already existing one and if you do not have a mirror, you can add the package to config/packages.chroot. In this case it is not necessary to specify any option.
There is also the possibility of making smaller changes. For instance, syslinux derivatives are configured by default with a timeout of 0 (zero) which means that they will pause indefinitely at their splash screen until you press a key.
To modify the boot timeout of a default iso-hybrid image you can edit a default isolinux.cfg file specifying the timeout in units of seconds and add it to config/includes.binary/isolinux/
A modified isolinux.cfg to boot after five seconds would be similar to this:
include menu.cfg
default vesamenu.c32
prompt 0
timeout 50
An alternative way of achieving the same goal could be writing a hook and adding it to config/hooks/ Remember to add the .binary suffix to run in the binary stage. A proposed example:
#!/bin/sh
sed -i 's|timeout 0|timeout 50|' binary/isolinux/isolinux.cfg
Likewise, if you want to use a personalized splash.png image you can add a picture of 640x480 pixels to config/includes.binary/isolinux/
When creating an ISO9660 binary image, you can use the following options to add various textual metadata for your image. This can help you easily identify the version or configuration of an image without booting it.