Xbox:Boot Animations

A custom BIOS will allow you to modify the boot animation and various other settings through a config file or BIOS editing.

M8+/X2 BIOS
Two builds of the same tool are used for editing M8+ and X2 BIOSes. For M8+, it is known as EVtool and for X2 it is known as XBtool. Select "Open..." in the bottom right to choose your BIOS's .bin file. From there, you can change the various settings and click "Save As..." when you are finished. You can flash the saved BIOS.

X3 BIOS
You can configure the X3 BIOS by using X3 Config Live, which is a built-in configuration menu for X3 modchips. Hold the white button on your controller while starting your Xbox, and it should boot into the X3 Config Live menu. This page has detailed instructions for how to use it.

Alternatively, for 1.0-1.5 Xboxes TSOP flashed with a hacked X3 BIOS, you can use X3 Patcher to configure some options, though VGA will not work on TSOP flashed consoles. Select "Open BIOS" in the bottom right to choose your BIOS file, and "Patch BIOS" to save it.

iND BIOS
Do not inject config files into the IND 5004 BIOS, it will brick your Xbox!

For iND BIOSes, you have the option to make your own config file into it using iND BIOS Config Maker. You can modify various settings or change the boot animation under the "Animation" and "X-Screen" tabs. It's important to decide whether to inject the config into your BIOS file or not. If you do inject the config into your BIOS, it risks bricking your system if the config is bad, but it will speed up boot time by about two seconds. If you just place the config file on the root of your C: drive, it doesn't risk bricking your system but will take the standard amount of time for iND BIOS to boot up. To inject the config file, select the Injector → "Inject .CFG into BIOS" and choose your BIOS file. Otherwise, select File → "Save CFG", and save it as ind-bios.cfg and place it on the root of your C: drive.