[Galaxy S III Q&A, Help & Troubleshooting] devnullius:
Trying to solve it myself - part xxx ;p

The following Google search brought some light to the end of the tunnel, I hope: http://www.google.com/search?q=stock+zimage+i9300+samsung&oq=stock+zimage+i9300+samsung&ie=UTF-8 .

It first brought me to this page: http://androidromupdate.com/2012/06/05/how-to-install-stock-rom-on-samsung-galaxy-s3-s-iii-gt-i9300/ .

There I learned the following (quote):

" Stock ROMs contains the binary and image files of the whole software packaged, like these:

* Sbl.bin

* cache.img

* factoryfs.img

* hidden.img

* modem.bin

* param.lfs

* zImage "

So I figured to let 7zip extract the stock firmware I downloaded (>700MB). Except for unexpected archive header warning, 7zip extracted just fine. I ended up with:

* boot.img

* cache.img

* hidden.img

* modem.img

* recovery.img

* system.img

From the chapter "For some reasons how to root the device info is here" (http://forum.gsmhosting.com/vbb/f200/galaxy-s3-i9300-flashing-root-guide-1483155/), I learned the following:

Quote: " According to Chainfire, the modification of the kernel was not as easy as done for the SGS I, SGS II, and SG Note, because, “…this time around, Samsung is using the standard boot.img format, instead of the zImage format used for SGS1, SGS2, SGNote, etc, that is much harder to repackage.”

This time around, the SGS III also has a separate Recovery partition, and unlike its predecessors, a custom recovery can now be flashed independent of the kernel."

So zImage is boot.img on i9300 - finally I learn something :> Also see: http://xdaforums.com/showthread.php?t=2022181 .

I was hoping that I could just flash this file with Odin. I have not tried it yet, for I first wanted to make sure that boot.img === kernel-to-flash :p

http://www.google.com/search?q=what+is+a+zimage brought me to http://www.embeddedarm.com/support/faqs.php?item=2 and especially http://xdaforums.com/showthread.php?t=1284986 . And brought many more questions - just flashing does not seem to be the trick? :(

So googling some more:

http://www.google.nl/search?q=is+the+(zimage.img+OR+boot.img)+the+same+as+the+kernel??&ie=UTF-8 brought me to: http://xdaforums.com/showthread.php?t=1477845 where there are instructions on how to split the kernel :s SIGH - why is this so hard??? Grmbl.

Quote: " At this point, we need a boot.img file to play with.

Pick your favorite custom kernel and get the .img.

Place it in a folder along with the 2 perl scripts from the attached package.At this point, we need a boot.img file to play with.

Pick your favorite custom kernel and get the .img.

Place it in a folder along with the 2 perl scripts from the attached package. "

And: " Can I do this on Windows? - Not that I know of, no. " SIGH!! :(

At this point, I'm about to give up again. One more page? http://www.freeyourandroid.com/guide/extract-edit-repack-boot-img-windows .

Quote: " boot.img is a small(ish) file that contains 2 main parts, the kernel (the brain of the Android system) and the ramdisk (a core set of instructions and binaries that begins the boot process and controls base aspects of the system, such as mountpoints, memory management and startup services). "

This looks promising! This solution works on Windows by installing Cygwin (Linux for Windows) and the for-mentioned scripts. I learned more AND I see confirmation for what I already learned...

Quote: " boot.img-kernel is the compiled kernel blob that was inside the source boot.img, if you want to replace the kernel with another compiled kernel image, you can replace this file with another one (but leave the file name the same)

boot.img-ramdisk.gz is the gzipped ramdisk image which has been split from the boot.img, you should leave this file alone.

The “out” folder contains the EXTRACTED ramdisk, and this is where you should make your changes to the ramdisk. "

This is something I definitely will try out tonight when I'm home - light again?

:) Peace!

devnullius

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Some further technical info and background reading with some nice tools: http://android-dls.com/wiki/index.php?title=HOWTO:_Unpack,_Edit,_and_Re-Pack_Boot_Images (from: http://xdaforums.com/showthread.php?t=1831027 ).