The GCOS BiOS is an open souce solution originally based on the Anaconda BIOS (code ripped from the Cobra BIOS) which features most of the functionality of all the other 3rd party BIOS and comes in many varieties.
Supported Boot Method/Device List
If you're wondering what features are in the BIOS itself you will want to check out the BIOS Comparison Chart for a list of them. Now on for the guide on how to use the BIOS. Of course you'll start at the main menu.
Main Menu Options
Boot Game
Once you select this option you will be asked to "Insert Media" so plop in your DVD and then press "A". Using the drivecode from SoftDev's emulators GCOS will try to boot your game. If it cannot it will tell you the "Media Wasn't Recognized" and then you can press "A" to Boot the Original IPL (GameCube BIOS) or press "B" to Retry.
Tools
Backup Game
If you would like to dump one of your original games to your hard drive simply boot GCOS up with your Broad Band Adapter (BBA) and pick this option. It will prompt you to insert your original disc. Once you press "A" it will display the Game's internal name, Date and Game ID. At this point you can type in the URL to the ISO which defaults to "http://192.168.1.32/backup.iso". I would use either Internet Explorer and/or Firefox and stay away from any download managers you may use.
Boot Real IPL
This will boot up your original GameCube BIOS. This is good if you need to manager your memory card and/or change the systems settings.
Disc Explorer
Pick this option and then press "Z" to continue. You can now browse your ISO9600 Discs for purposes such as running DOL files. Note that if you run the Disc Explorer with an original game in the GameCube and then return to the main menu and try to read an ISO9660 Disc GCOS will crash.
LAN Explorer
Using the server software that comes with the special version of GCOS entitled "GCoS Remote Loading Server v1.0" you can browse your computer's hard drive and run applications and/or stream images from it. You use this option to connect to the server running on your PC.
Misc
Action Replay
This option will simply let you boot an Action Replay disc/backup so you can cheat in your games. Pick it, insert your disc and then press "Z" to continue.
Boot Original DVD
I hope you can figure this one out by yourself.
GCOS 1.4 Boot Method
If you are having problems booting some DVD's that would boot under GCOS you can opt to use it's drive code using this option.
Grab FST
When I figure out what this is I'll let you know.
Dump Drive Firmware
Using this option you can dump the GameCube's Firmware. Once you select this option simply point your web browser to "http://192.168.1.32/DFW.DAT".
Settings
IP, Subnet, Gateway
You can change the default settings for the Network Setup here. Not needed if you do not own a BBA or run a 192.168.1 network. More Settings -> Region Check
You can toggle GCOS to always ask you which region to boot the game in using this option.
Documentation
Help - Displays a quick help file
Credits - Displays the massive list of credits
More Stuff
You can upload DOL files using tools such as d0lLZ, Netcat and/or DolStream. Simply upload your file of choice to http://192.168.1.32 port 4000. Please see our Streaming Guide for information on how to use these sending applications
Additionally, you can dump the GameCube's Memory, IPL or REALIPL by using the following URL's.
http://192.168.1.32/MEM
http://192.168.1.32/IPL
http://192.168.1.32/REALIPL