IMPORTANT
After peforming this hack the xbox 360 can only run homebrew not xbox games or dash unless you install a cynos chip, run the mod f/w on cynos chip and std f/w on the onboard nand chip or vise verser and switch between the 2 depending on what you want to run. If you do update with the latest xboxlive update homebrew will never run on that xbox again even if the update is done after the mod.

What you need

xenon xbox360
5x 100ohm resistors
3x 330ohm resistors
1mtr kynar wire
1x old printer cable
(the type that you can unclick the plastic end bits to change pin config of the wires)
pc with a printer port that operates in spp mode
(standard parallel port) most old pc's but some new pc's have it
nandpro (put nandpro20 folder in the root of c drive)
dlportio (comes with nandpro)
xenon_hack.bin file (rename to hack and put in nandpro20 folder)
hex comparison (or a md5 hash program)


What you need to do
1. solder in the lpt/jtag wires (as in the picture attached to this tutorial)
2. boot your pc to the bios settings ans set the lpt to spp mode
3. boot to windows xp (vista is incompatible) install dlportio driver and reboot pc
4. in the windows start menu click on run and type in command then press enter (opens command prompt)
5. plug the power into your xbox360 (does not need to be turned on) plug the lpt port into the pc
6. in command prompt type c: andpro20 andpro.exe lpt: -r16 nandbackup1.bin
7. in command prompt type c: andpro20 andpro.exe lpt: -r16 nandbackup2.bin
8. compare with hex comparison (if files are different repeat step 6,7,8 until they match so you are sure of a good backup)
9. in command prompt type c: andpro20 andpro.exe lpt: -w16 hack.bin
10. remove the lpt cable from the pc and boot the xbox360 and you should have a blue screen with writing (if you dont you *****ed up and need to repeat step 9)
11. unsolder the lptjtag wires but leave the ones with the 330ohm resistors they need to stay for life
12. just pop in a usb stick or disk with the desired apps or emulators and enjoy


Picture


Thanks realaspe for the picture

Tutorial credit I do not claim