Image type for img2

[tmac9010]

hey guys,
i used the rainbow apple provided by ChronicDev(thank you) and now i want to make a custom recovery logo. what is the image type that .img2 is or what type of editor can i save images as .img2? thank you

[DJ McG]

I would like to know this too. I tried searching google but I couldnt find anything...

[skygear]

i'm not around my iphone at the moment..... but has anyone tried to rename it? i tried a few file formats and no go.... i imagine when the ipsw tool is released by chronic there will be an image convrter

[Sproglet]

It's not an image file...it's an image embedded in a custom apple file.

If you do a strings on the file you get entry's like:

Apple Secure Boot Certification Authority
Apple Certification Authority
Apple Root CA

So it's clearly a file that's been signed...(then the sig is ignored thanks to pwn)

I have to get up in 4 hrs so I don't have time to investigate further just now but I'm sure the dev team or someone will put out the details soon :)

[tmac9010]

it is encrypted like crazy you need to use 8900decryptor(i heard) but i dont get it why cant we just add the extension .img2 if the bootloader doesnt need signed things?

[JEsTer]

yes you can decrypt it with 8900decryptor. but it is still unrecognizable file type after decrypting. somehow the resulting file has to be converted to a working .png, but i can't figure that out. Then after that, still have to figure out how to put it back to .img2 maybe?

[drg]

it is encrypted like crazy you need to use 8900decryptor(i heard) but i dont get it why cant we just add the extension .img2 if the bootloader doesnt need signed things?

I think you are confusing encrypted and signed. The signature won't matter after pwnage, but the encryption still does.

[tmac9010]

ok i got it so why cant i just change the extension of a .gif to a .img2 and put it into my custom ipsw?

[xMemphisx]

ok i got it so why cant i just change the extension of a .gif to a .img2 and put it into my custom ipsw?

Because when the bootloader goes to access the file, the first thing it attempts to do, is decrypt the image... if it can't decrypt it... it won't access the file.

[Sproglet]

The file format info is here:
http://wikee.iphwn.org/s5l8900:8900_format

And the decrypter code is here:
http://code.google.com/p/iphoneelite/wiki/8900decryptercode

Now all we need is encryptercode :)

[CU3BALL]

But as far as I see from the file format description it is also possible to define in the header, that the actual data is not encrypted. So by setting the 8900_header_format to 0x4 it should be possible to save the data unencrypted.

[Sproglet]

Decrypting the file still doesn't give an image format...


Running Strings on the decrypt file gives:

2gmIogol
srev
EmbeddedImages-5
iBootIm
sszlbgraL

before the "data"

Now I don't recognise any of these as file headers off the top of my head... anyone else?