[Q] How do I backup my stock kernel and flash a new one? - Galaxy S II Q&A, Help & Troubleshooting

These are my phone specs
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I am running Stock ROM with root and CWM recovery and Kernel of ICS 4.0.3. I want to flash a different kernel(just the kernel), but backup my old(official one) in case I need to flash it back.
So, how do I backup my original kernel, in a easily re-flashable format and how do I recognize unsupported/supported kernels for my stock rom?
Also, is it true it's much harder to flash kernels(perhaps the original) on a stock rom, than a modded one?

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You can try flashing Siyah Kernel either the CWM or Odin ones.
You don't have to backup your stock kernel as it can be easily download in XDA
example from Intratech Thread...
Siyah Kernel:
http://www.gokhanmoral.com/
Stock kernel from Intratech:
http://forum.xda-developers.com/showthread.php?t=1075278
Good Luck & Happy Flashing.

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Right, I downloaded the official kernel, just to have it backed up, but it's in a zImage format, not in a zip. How would I go about flashing it back via CWM recovery?

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dikidera said:
Right, I downloaded the official kernel, just to have it backed up, but it's in a zImage format, not in a zip. How would I go about flashing it back via CWM recovery?
Click to expand...
Click to collapse
For zipped tar format try here:
http://forum.xda-developers.com/showthread.php?t=1640812
---------- Post added at 10:05 PM ---------- Previous post was at 09:53 PM ----------
dikidera said:
How would I go about flashing it back via CWM recovery?
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Click to collapse
From CWM Manager, select Flash Kernel, and select the zImage you previously put on your SD-card. The kernel will flash and the device will reboot.

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I dont have any Flash kernel option in cwm recovery. And the link to the tar is for Odin, not for CWM

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dikidera said:
I dont have any Flash kernel option in cwm recovery. And the link to the tar is for Odin, not for CWM
Click to expand...
Click to collapse
Not CWM recovery. He said to use the CWM Manager app in your app drawer. It should be there if you flashed a CF-root kernel.

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I have not flashed any kernel yet since i cant be sure if I can flash the original back. Does siyah provide this cf-root?

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dikidera said:
I have not flashed any kernel yet since i cant be sure if I can flash the original back. Does siyah provide this cf-root?
Click to expand...
Click to collapse
Siyah and CF-Root are two different kernels.
Both have forms of CWM Recovery packaged with them, but they will be slightly different.
I think you need to read some more.

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Hi,
you said you rooted your phone ???
I am running Stock ROM with root and CWM recovery and Kernel of ICS 4.0.3.
Click to expand...
Click to collapse
i dont think you can backup the stock kernel just go there:
http://forum.xda-developers.com/showthread.php?t=1640812
are all zip - so u can flash via CWM

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Kernel != ROM.
I might be rooted but I did it straight from the phone.
I just want to flash a different kernel just for the fun but with the ability to flash the original back, get it?
The link that was given to me has kernels in tar format or whole roms

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if you got stock your NOT rooted..
link works fine for me with *.zip files which can be easily flashed in cwm recover (vol up + power + home)
roms come WITH a kernel
just click the link above - dll your xwlp7 stock kernel and try CF Root (for beginners)
get it?

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But I don't want the rom, just the kernel. And just as an fyi, I used the root method which doesn't require flash with Odin. Yes I have the Superuser app.
My 3g is so slow that by the time i download any rom it will be 2022. Kernel is smaller thus dlfaster download(sort of)

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Um ok which method is this? (this one? http://forum.xda-developers.com/showthread.php?t=1679778 ? i9100G?) i think i already read this but didnt try - i used to flash via odin at the beginning now i go for CWM Recovery to flash ;-) i only root per Kernel..
Link posted before still work fine - those are also (or only) Kernels
so i still dont get your Problem
Just go for any (supported) Kernel and flash - if you+re not happy go back and flash stock kernel (dll before..)

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Cwm recovery requires zip files whig have boot.img inside them just like the siyah kernel, but the original kernel is just a zImage file produced when the Linux kernel is compiled and I don't think its fit for flashing

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CWM Recovery is like Download Mod - you can get there via "the 3 Buttons."
I think you talking bout CWM - the Touch Version of it?
You need the zip file Kernel - could you give me the link to your stock kernel which is in (you say) zImage?

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This is the one I downloaded http://skywanker.net/download/download.aspx?link=GT-9100/Kernels/Kernel_I9100XWLP7.7z

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I'm sitting in the same boat and sorry to Jack your Thread, But do you know when you flash a Kernel, does it need to be rooted before hand or not? "Auto-Root" is on the Specifications so a little confused :fingers-crossed:

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dikidera said:
These are my phone specs
I am running Stock ROM with root and CWM recovery and Kernel of ICS 4.0.3. I want to flash a different kernel(just the kernel), but backup my old(official one) in case I need to flash it back.
So, how do I backup my original kernel, in a easily re-flashable format and how do I recognize unsupported/supported kernels for my stock rom?
Also, is it true it's much harder to flash kernels(perhaps the original) on a stock rom, than a modded one?
Click to expand...
Click to collapse
According to this, you still have your stock kernel, right?
So it also sounds like you just want to dump your current kernel as a backup. In that case, just download HC-kTool from the Play Store. It will allow you to dump your current kernel. It also allows you to backup your EFS, which is useful.
---------- Post added at 03:55 PM ---------- Previous post was at 03:54 PM ----------
Jordan2012 said:
I'm sitting in the same boat and sorry to Jack your Thread, But do you know when you flash a Kernel, does it need to be rooted before hand or not? "Auto-Root" is on the Specifications so a little confused :fingers-crossed:
Click to expand...
Click to collapse
No, you do not need to be rooted before flashing a kernel, and in fact, some kernels, when you flash them, will root your phone for you.

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That's good to hear, Also my is Phone is under Contract With Three (3) will everything be alright for example minutes I don't wanna end up unable to use my SIM? :')

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Jordan2012 said:
That's good to hear, Also my is Phone is under Contract With Three (3) will everything be alright for example minutes I don't wanna end up unable to use my SIM? :')
Click to expand...
Click to collapse
Just be sure you use firmwares/kernels meant for your device.
For example, if you have an i9100, do NOT use a firmware or kernel for an i9100G, or any other device.