Hacking Compress NAND backup of 32 GB Wii U

[pLaYeR^^]

I got a used cheap Wii U with 32 GB NAND. I created a backup of the NAND but when I compress it (.rar or .zip archive), the archive is still about 18 GB. The NAND is clean (format before hacking). A year ago I hacked a Wii U for a friend and after compressing the NAND the archive is only 3 GB. Is there a way to get the archive to 3GB? Thanks in advance

 

[tmnr1992]

I didn't even know it could be compressed, I just assumed it would be the same size, but I'm guessing it has something to do with the actual size of your nand, for example your nand will be smaller in size when compressed if it has no games installed. As I said I'm not entirely sure, I'll try compressing my nand dump and report the results later.

 

[godreborn]

it's probably the size of the NAND (32 or 8GBs) and whether or not something is installed. no matter what, the size of the NAND will be a certain size when dumped. I think it has to do with the manufacturer or the NAND chip, 'cause I've seen 29.1GBs and 29.7 or something like that.

 

[YOUCANTSTOPME]

Depends what's installed on the system. Note that even if you delete stuff on the console, it may be marked as deleted but there may still be remnants in the NAND remaining, and that leftover junk data could still be present and be getting compressed.

Did you do a system format before setting up your "new" Wii U?

 

[godreborn]

tickets will remain even if you uninstall content. I don't really know why that is. however, that's on the slc partition.

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this happens on the 3ds too, I just remembered. I periodically clean my 3ds of any tickets not being used.

 

[pLaYeR^^]

@tmnr1992 @godreborn There weren't any games installed.
@YOUCANTSTOPME Yes, I formatted the Wii U even twice.

 

[godreborn]

not sure then. I've never compressed my nand. your friend's system was probably an 8GB.

 

[pLaYeR^^]

not sure then. I've never compressed my nand. your friend's system was probably an 8GB.

No, it's a 32 GB one. My friend still owns it and it's black.

 

[YOUCANTSTOPME]

I can't think of any realistic solution other than finding out a way to wipe the old deleted data.

 

[pLaYeR^^]

I can't think of any realistic solution other than finding out a way to wipe the old deleted data.

Yeah, it seems there is still data stored even after system format.

 

[godreborn]

that's odd. I'd imagine empty space is represented by 0s or Fs. that would compress smaller. I actually made three separate backups of my nand, and I didn't compress any of them:

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I'll let you know how much it compresses with the original.

 

[KleinesSinchen]

I'm genuinely surprised (significantly) compressing a NAND dump (encrypted data ≙ random data) is possible at all. If you create an encrypted file system somewhere, it looks from the oudside (without the key) like random data – even if the decrypted, plaint text consists only of 0x00 or 0xFF bytes.

My wild guess: The NAND chip comes full of 0x00 from the factory. In the console manufacturing process encrypted data is written – but without overwriting unused parts which stay on 0x00. This would lead to a NAND chip that has about 3 or 4GB actual data (operating system) on it and the rest are zeroes. If you use your Wii U for save data and installing games previously unused parts get used. No matter what you write inside the encrypted file system, from the outside it should look like random data.

What I want to say is: Each sector that has been used once will forever be random data from the outside and cannot (really) be compressed anymore.

 

[godreborn]

it compressed less than 1%: