Ok, here's how to do that. too... Xenium isn't 100% slayers installer compatible. You need to get a bios on there that allows it to read backup media before it'll run Slayer's installer.
First thing you need to do, get another CD, DVD,CDRW, ect.
Find the Bios you want. (I personally use a 1 meg Xecutor2, all though I am diehard loyal to OzXodous chips)
NOTE: All the Bioses(if that's even a word) you need are in the slayer's xiso. Just dig around for them and you'll find a dirrectory full of them labeled as to what they are, you'll just have to pull them out and rename them to bios.bin.
Burn a 100meg or so file to that CD folowing the normal CD burn method make sure to rename that file AAAA.AAA so it burns first to the CD (This is your buffer or pillow file, still no clue why we do this anyways, my sammy reads fine w/ or w/o one) You want to rename the bios you found to Bios.bin, and burn that to it too. it should be the seccond and last file.
Stick that in your Xbox, and boot up, hit the white button for the menu. Select a bank config for the bios size you just burned. Then flash.
Now go to the bank config menu. Select the bank you want to flash. then go to d:/bios.bin. Flash it. save your settings.
Now boot up the new bios you just installed onto your modchip (I made it default) w/ the evox CD inside the drive. Evox should boot up off the CD if done correctly.
Slayer's is good stuff it just doesn't have the d:/bios.bin file you need to install, and that has to be installed in Xenium OS, as opposed to the installer.
Hope that clears it up. If it works you've jsut gotten past the trickiest part of modding your Xbox.