Swizzy release today a little tool for corona 4GB owners that wants to read/write the nand easily. There is two features in this tool :
– Dump the nand : System only (48mb) or full dump (3.5GB)
– Write an image to nand.

Read the « requirements » part of the readme to make it work properly.

Full Readme :

nandMMC
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* Requirements *
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– Microsoft .NET Framework 2.0 or later
– A SD Card reader or similar that is connected to your Corona 4G motherboard
– An Xbox360 with Corona 4G Motherboard
– Administrator rights. You must run this application as an administrator!!

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* What it does *
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– It’ll dump your motherboards NAND to specified file, with specified size
– It’ll flash your motherboards NAND with specified file

** NOTE: It will only dump/flash if it finds the magic bytes (0xFF4F at the beginning) **

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* Credits *
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– cOz Thanks for all the help you constantly give me with just about everything! :D
– Aioros Thanks for the logo as ussual ;)
– Razkar Thanks for making me a perfect icon!
– boflc Thanks for giving me the tip for the final name of the app ;)
– Thanks to everyone that has helped me test this and make sure it really worked! ;)

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* Changelog *
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v1.0 (Build: 20)
– Initial release