Change/Install custom kernel [GUIDE]

· by · in Tutorials. ·

In this post I’ll show you how to change your kernel and flash new /better one .
Requirements:
1. Flashtool
2. Kernel file – usually looks like this ( boot.img)
3. Unlocked Bootloader

Before we start there are few things you should know about the Kernel of Android.
“Do I need to change my Kernel and why I should do that ? ” 
Changing the Kernel is completely up to you but as we know the Kernel represents the connection between the hardware of your phone and the software, so that means if we have a better Kernel we can get more performance or better battery life  of our Smartphone.

“Isn’t the stock Kernel good enough ? ”
The stock Kernel that comes with your phone is good If you not use your phone for anything different than calls and Facebook. But other Kernels allows you to overclock your CPU for better performance, undervolt for better battery life and many more things that the stock Kernel is restricted to do.

“Can I install any Kernel that I want ?”
No. You can’t. There are ROM’s that have exactly written Kernels for them  so for example:
Stock ROM = Stock Kernel
Cyanogenmod ROM = Cyanogenmod Kernel
JellyBean ROM = JellyBean Kernel and etc.

So let’s proceed with the installation. Shall we ?
There are 2 known methods to get your new kernel working.

First Method is using Command Prompt.
1. Download and extract this file.
2. In the fastboot folder you extracted you should copy the Kernel file( For IceCream Sandwich 4.0.4 I recommend xKernel by sirkay
3. Power Off your Device and get into Fastboot mode (Hold Volume UP and connect to USB) If you done everything right the LED of your phone should light in Blue.
4. Open Command Prompt and navigate to the folder you copied the boot.img or just Shift + Right Click -> Open Command Window Here (In the current directory)
5. Then type

fastboot flash boot boot.img

6. If everything went smooth you should get a message that flashing went okay.
7. Unplug your Device and Power on .

WARNING: IF YOUR PHONE DOESN’T START(BOOTLOOPING) YOU INSTALLED KERNEL NOT SUITABLE FOR YOUR CURRENT ROM. FIND DIFFERENT KERNEL AND REPEAT AGAIN.

Method 2 using FLashtool.
1. Open Flashtool
2. Connect your phone in Fastboot mode.
3. On Flashtool choose the Flash Icon and select fastboot mode.
4. Choose Select kernel to Flash and find your Kernel (boot.img)
5. If everything went smooth you should get something like this:

6/032/2012 15:32:12 - INFO - Selected kernel (boot.img or kernel.sin): D:\xperia mini important\update-cm-7.2.0-RC0-XperiaMini-ST15i-KANG-signed\boot.img
16/032/2012 15:32:12 - INFO - Flashing selected kernel
16/032/2012 15:32:14 - INFO - FASTBOOT Output: 
sending 'boot' (4512 KB)...
(bootloader) USB download speed was 9333kB/s
OKAY [ 0.501s]
writing 'boot'...
(bootloader) Download buffer format: boot IMG
(bootloader) Flash of partition 'boot' requested
(bootloader) S1 partID 0x00000003, block 0x00000148-0x00000179
(bootloader) Erase operation complete, 0 bad blocks encountered
(bootloader) Flashing...
(bootloader) Flash operation complete
OKAY [ 0.873s]
finished. total time: 1.374s

16/032/2012 15:32:14 - INFO - Please check the log before rebooting into system

7. Unplug your phone from the USB and reboot.

WARNING: IF YOUR PHONE DOESN’T START(BOOTLOOPING) YOU INSTALLED KERNEL NOT SUITABLE FOR YOUR CURRENT ROM. FIND DIFFERENT KERNEL AND REPEAT AGAIN.

OVERCLOCKING

1. Download No CPU Frills from Google Play Store
3. Maximum overclocking depends completely on the Kernel cap’s
4. Maximum overclocking may harm your device or cause your device to be unstable (random reboots)

12 responses to “Change/Install custom kernel [GUIDE]”

  3. I am so lost. I have a Nexus 4, and the battery keeps dying. I tried installing jelly bean but don’t know how to switch kernel

    • You dont have to install custom ROM. You just need to make sure the kernel is supporting your Android version. And by that I mean that you can’t apply Kernel from JellyBean to IceCream Sandwich ROM. There is a lot of information on XDA.

  6. Thank you for your reply, I’m new to this and needed some help, I have a rooted Samsung galaxy note i717 and need to flash a kernel that has the bln mod in it so I can use the touch keys light as a notification light. So what kernel would I flash without using a custom rom?

  8. Well you need to search for ICS Kernel in that case. I am not familiar with the custom kernels and rom’s for the Samsung devices, so I will leave the searching for you. Let me know if you have any further questions.

  9. hyeee…i want to ask you..if we want to flash a new kernel..we should unlockbootloader first right?? i’m using experia ray..after 1 month my experia ray upgraded to jellybean..my phone become unstable..it cannot detect by pc even i cannot charge my phone..now i downgraded it to ics..same problem happen..if i flash this kernel to my phone..did it solve the problem??? -sorry for my english-

    • Is there official Jelly Bean ROM for ray ? If you want only to downgrade your Firmware version you dont need to unlock your bootloader. All you need to do is find the official ICS ROM .ftf file and reflash it with Flashtool.
      This is a thread with useful downloads and stock .ftf files and other useful stuff -> Link here.
      How to flash stock .ftf file check out here -> Link here

      Otherwise if you want to flash a new kernel, yes you have to unlock your bootloader.

      • i already downgrade it..but my phone cannot charge and detect by pc..maby the kernel not suitable with the android version?? help me to fixed that problem..can you??

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