there are many ways to create a bootable pen drive , try the tutorial
here , then once you have done that..........
Download the file ixtreme15.RAR from team-xecuter.com
Open up the file and extract the folder DOS
Put the contents of the DOS folder into the root of your bootable USB stick
Copy your created hacked.bin ( or whatever you have named it ) file into your bootable USB stick
Now turn Off your drive
Load up your newly made DOS bootable USB stick
Wait for the C: or A: to appear
At the prompt type in L-O-eras.exe ( address of your sATA card )
For example -----> L-O-eras.exe 9000
Before you press Enter turn On the drive
Press Enter, it should say FF80 or FFFF
Type in L-O-eras.exe ( sATA card address ) again and press Enter
Should now show FF72 or something with 72 in it
Turn Off the connectivity kit and back On
( this is important or else itll say unknown chip type when trying to flash )
Now at the command prompt type dosflash and press Enter
Press N (if it asks) until it asks what number drive you are using
It will then give you options of Write or Erase etc....
Press W for write and itll ask for filename
If it says unknown chip type you didnt power the drive Off/On
Type in the name hacked.bin or whatever you called your modded file
Press Enter and itll begin to erase then write the 4 banks
Once it shows a checksum the jobs a good one
Turn off the connectivity kit and reboot windows
Put Xbox back together and test
^^^copy/pasted from a post on these forums , cant remeber the original poster but all credit goes to whoever it was