Full details can be found here :
Phantasy Star Online game
Fire up your copy of Phantasy Star Online and head on over the to options menu. Choose network option, provider option, and then yes to go into the network configuration screen. When you are at the configuration screen select network setup and choose "manualy set an IP address". Press the next button and enter 192.168.1.32 for the IP address, 255.255.255.0 for the subnet mask, 192.168.1.100 for the default gateway, and finally 192.168.1.100 for primary DNS. After entering in the info press next and save your settings to memory card.
Lets assume you have all the files needed for this tutorial as well as your games and or homebrew apps in the following directory (c:\gc) Open up a windows command Prompt by typing cmd.exe in the run box. To change into the directory type "cd gc" and press enter. Next type "psul.exe -s" and you should see the following.
Now on PSO choose the Online Game option at the title screen. Follow the onscreen directions and create your character. After you have created your character and saved it to the mem card and the game asks if you agree to the user terms say yes. The game will begin to load and you will see a warp hole type screen. At this point the game is initializing the Gamecube BBA for connection and you should pay attention to your command prompt screen to verify you have received the messages that your content is being saved on the memory card.
To upload a Gamecube game or homebrew app:
Lets assume you have all the files needed for this tutorial as well as your games and or homebrew apps in the following directory (c:\gc) Open up 2 command prompt windows by typing cmd.exe in the run box. Go into the directory where all the files are by typing "cd gc" and press enter. In the first command prompt window type "psul.exe eur-acl1.dol" and press enter. By doing this the Eurasia loader will be sent to the Gamecube once the connection has been made. In the second command prompt window type "eur-acl1.exe eur-acgc.gcm" and press enter. This will send the game/homebrew iso to the Gamecube after you have selected the boot method on the Eurasia loader screen and pressed start.
After putting both the loader and iso/gcm in standby mode boot up your Gamecube with PSO in. At the title screen choose Online game and agree to their terms of service. Again you will see the warp hole screen and the bba will once again initialize. At this point the Eurasia loader will be sent to your Gamecube and wait for you to make your selection. Select between boot mode A or B by pressing right or left on the controller d-pad. Use boot method A for animal crossing and boot method B for anything else.
On some sytems the entire game will load in 1 minute and on other systems this process may take several minutes! Please be patient, As long as dots are filling the command prompt screen then Animal Crossing is loading.
If you are having problems with hanging, or the console is filling up with X's and or transfer rate is very slow, try using the delay switch to slow down transfer rate from PC.
To delay usage at the command prompt type "eur-acl1.exe eur-acgc.gcm -d10 -f16" Delays 10ms every 16 packets.
If no -f switch is given the frequency of delay will default to every one packet which is far slower and perhaps no more reliable that of a given frequency value. Experiment with different values for both to find the best option that works best for your current set up.
All screenshots and complete details can be found here
If you find another LEGAL exploit , feel free to add it to this topic.