I have this guide in the gold forums I personally follow it and other users have used it and told me it worked fine so here you go.
Before you go ahaead and read all of it a heads up you will need your own XeBuild and in this method we use Flash360, i dont know how it works with Simple360nand flasher or whatever other programs are alike it.
Well, you will need two programs. One called "Flash360", which is used to get the nand image from your RGH/JTAG console. Also, you will need a program called "xeBuild". Now, xeBuild is used to create an updated hacked image,
in simple terms its used to update your Xbox 360 dashboard.
Now that you have downloaded both "Flash360" and "xeBuild". You will need to get your nand image. To do this, extract Flash360 to a USB and stick the USB into your console. Now after that, open the folder, and run the .xex inside.
You should now have Flash360 up and running, press X on your controller to "Backup current Nand to file", then press A to "Save entire nand to file" Once that is done, you should see a message on screen
"Press any button to continue", so press a button. This is not an optional step, we will need this for the next step.
Now, go back to your computer and open up xeBuild. Select the "Open" button, and go into your USB, and the folder called "Flash360". Now, we are looking for the file inside that folder, that's called "flashdump.bin".
Select it and then move on to the next bar, which will ask you to choose an output path. So, select "Save", and I advise selecting your Desktop, or somewhere you can easily find the outputted file.
Hopefully you are following alone so far, not much more to do now. Go back to your console and open Dashlaunch, there you will be able to see your consoles CPUKey. Enter the CPUKey into the program,
(Make sure you haven't made a mistake) After you done that, select "Kernel version" dropdown menu, at the bottom of the program and select the current Dashboard.
Now all that is left for you to do on the computer, is select the "Generate hacked image" button and wait for it to complete. After you've done that, check for a file called "updflash.bin", it should be where
you selected the output patch.
Last step, is to flash the file named "updflash.bin" to your nand image on your console. To do this, go back onto the Xbox 360 and open up Flash360. Place the "updflash.bin" file, into that folder and follow the following instructions:
Press A to "Write updflash.bin to Nand", then select A again, where it says "Raw Flash with keeping current kv/config" Then, press A and A once more. Okay, Now it has started writing the "updflash.bin" to your console.
Wait for that to complete, then press any button to continue, and then the back button on your controller twice. Okay, this is where it is important, you will need to unplug every wire, including power and AV/HTMI for a full minute.
After that, plug all the cables back in and boot up your console! You should now have an up to date modified console!
Cookie i think your alright man. updating nand is a simple process for the most part cookie broke it down literally step for step but in other words you need to dump your current nand, run it through the latest xe build then you will be left with a updflash.bin. you can stick the updflash.bin on a usb , plug usb into console and boot via xell. I'd recommend using a program like flash 360 but xell is another method, just make sure you use the latest xebuild to create an updated nand. check out ninja stealths website for latest xebuild files, they even provide a video on how to rebuild your nand.