The softmod for xbox1 is extremely awesome. I can mod an xbox in under 7 minutes, without voiding the warrenty.
What you will need (method 1):
Original disk of 007 agent under fire, mechassult or splintercell
Modded xbox
Memory card
ability to connect xbox to your PC
The save exploit for the game you chose above
Dashboard exploit of your choice.
1. Using a modded xbox, tranfer the contents of the save exploit zip (the one I have been using for years is MechassaultwithEvox.rar) to the E drive via FTP. Then use the original M$ dash or unleash x to tranfer the save to a memory card. Note: instead of using a save exploit that boots into evox, you could use an autoinstaller, but I don't know how well those work.
2. On the unmodded xbox, transfer the exploited save to the hard drive via the M$ dash.
3. Load 007, etc. then load the save. The screen should go blank and evox should appear. Change the network settings to fit your network (im not going to go into that here) and reboot if nessesary.
4. Unzip the contents of your dashboard exploit and ftp them to the unmodded xbox. Where exactly you transfer them to veries greatly based on which one you choose. I am currently using uxe-complete-v0.2.2.rar and I like it. With that one, backup your C drive to your PC, then erase it. Put the place on C files on C, and the place on E files on E. Instructions will likely be included. Upon restart you now have a softmodded xbox. If you opt to install a live friendly exploit like the double dash or audio exploit instead of uxe, the install and usability will be different, but instructions should be included.
Summary: Copy save exploit files to memcard on modded box, copy from mem card onto unmodded box, ftp into unmodded box and install dash exploit files.
Alternate Method: This method is far more risky, but it requires far less materials.
What you will need:
Desktop PC near the xbox
Softmod files of your choice.
Linux live CD capable of reading xbox drives.
1. Take the xbox apart so that you can remove the hard drive. Move your xbox close to the computer, turn the xbox on (without a game in it), make sure the AV cable is connected too (but it doesn't need to be connected to a TV, just the xbox).
2. Burn the xbox live CD on your computer. I think you can also use xbhdm which is a varient for installing new hdds.
3. While the xbox has been on for at least 10 minutes and the PC is off, disconnect the ide cable from the xbox and connect it to the PC. Be sure to leave the power cable alone. Turn the PC on and boot the livecd. The reason why this dangerous hot-swap must be done is because xbox drives are locked. The xbox bios unlocks them, and your PC bios can't. The 10 minutes is to wait for the drive to spin down.
4. Manually transfer the uxe files to the appropriate places on the xbox hdd.
Reconnect the xbox hard drive to the xbox and restart and it should be modded. If you screwed up, you can repeat the proccess even if it won't boot to M$ dash.
Summary: Connect Xbox hard drive to PC, boot linux cd, transfer files to appropriate places.
Pimpin' Out steps:
1. Evox is kinda an outdated dash, so I like to use UnleashX which supports 3d backgrounds, PCless skin downloads, video skins, background music, etc. Assuming your using the UXE exploit above, simply go to the root directory it made on E drive, erase everything there and copy the contents of your unleash x zip there making sure the executable (.xbe) is called default.xbe.
2. There is a file I made called krakendash. Using it, you can access the original xbox dash on a softmodded xbox. I kinda botched distrobution of it though so its probably near impossible to find nowdays. Maybe i'll rerelease it on the PS2nfo IRC channel if there is demand.
3. New versions of xbox media center have a skin that makes the xbox1 look and play like a 360 (but not its games of course). Its pretty awesome, so check it out.
Note: All files besides the linux cd are made with the xdk and thus cannot be legally distributed here or at any other site.