BIOS Dumping
From xboxdevwiki
Dumping a BIOS can be done in several ways.
Using a chip reader
The BIOS is an ordinary TSOP and can be read with an ordinary TSOP reader.
Using a softmod exploit
Using a softmod exploit, you can usually choose to 'backup' your Xbox. This dumps a load of information to E:\Backup, including the BIOS. You can then FTP into your Xbox and retrieve it.