Shortcut for building AOSP tree with new kernel

[Fred]

Hi,

 

I am making some test building the AOSP tree of one of the branch of kitkat for a pandaboard, I did it using the prebuilt version of the kernel. Then I wanted to build a compatible kernel and create android build with this new kernel.

 

After build the kernel I placed the kernel file under /dev/ti/panda/kernel and just type make clean and then make. This will build the AOSP tree again and i will get my new kernel in the build but i will take quite some time.

 

I guess there is a smarter (and faster) way to create differents android builds when the only change is the kernel. Have any of you solved this?

 

Thanks and regards.

 

Fred.

[Benoit Fouet]

Hi,

On Thu, Mar 13, 2014 at 01:02:32PM -0700, Fred wrote:
> Hi,
>
> I am making some test building the AOSP tree of one of the branch of kitkat
> for a pandaboard, I did it using the prebuilt version of the kernel. Then I
> wanted to build a compatible kernel and create android build with this new
> kernel.
>
> After build the kernel I placed the kernel file under /dev/ti/panda/kernel

> and just type *make clean* and then *make.* This will build the AOSP tree

> again and i will get my new kernel in the build but i will take quite some
> time.
>
> I guess there is a smarter (and faster) way to create differents android
> builds when the only change is the kernel. Have any of you solved this?
>

Have you tried 'make bootimage-nodeps' (see build/core/main.mk)

--
Ben

[JF Dionne]

make bootimage OR delete the kernel and boot.img files in your out folder and rerun make

[Dave Turvene]

On Thursday, March 13, 2014 4:02:32 PM UTC-4, Fred wrote:

After build the kernel I placed the kernel file under /dev/ti/panda/kernel and just type make clean and then make. This will build the AOSP tree again and i will get my new kernel in the build but i will take quite some time.

 

I guess there is a smarter (and faster) way to create differents android builds when the only change is the kernel. Have any of you solved this?

I did some pandaboard kernel development back when and found the makefiles are best structured for a first-time build, which is great but means they are slow for build cycles.

Yes "make bootimage-nodeps"  is a clean way to make just "boot.img".   I have a couple additional thoughts.  I don't have a running pandaboard at the moment so this is taken from my old build scripts.  And I used the linaro baselines, which are different from the AOSP (e.g. uboot instead of the Android bootloader).  So you will need to massage these thoughts some for your testbed.

I use $(PRODUCT_OUT) as a short-cut for the shell functions in envsetup.sh, $(get_abs_build_var PRODUCT_OUT)

1. backup the current $(PRODUCT_OUT)/kernel so you can recover a working kernel if something goes bad

2. copy the new kernel zImage to $(PRODUCT_OUT)/kernel

3. make bootimage-nodeps creates a $(PRODUCT_OUT)/boot.img containing your kernel.  MUCH faster is to use the umkbootimg, boot_info, mkbootimg utilities (google for downloads) to update boot.img.

4.  Load JUST the boot.img onto the pandaboard.  system.img requires all the vendor proprietary shared objects, which I found to be tedious/slow for kernel work.  Use "fastboot boot $(PRODUCT_OUT)/boot.img" on a running system to boot your image but NOT overwrite internal flash.  If you are putting it on an SDcard use dd to overwrite the by-name LNX partition.  This is generally the first partition on the sdcard.

Good luck!

[Jean-Baptiste Queru]

I don't know if PandaBoard supports it, but IIRC the most common approach about testing just the kernel is to boot the new kernel over fastboot with fastboot boot <kernel>, instead of flashing a boot.img each time.

JBQ

 

--

Jean-Baptiste M. "JBQ" Quéru
Architect, Mobile, Yahoo

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[Dave Turvene]

On Tuesday, March 18, 2014 11:44:13 AM UTC-4, JBQ wrote:

I don't know if PandaBoard supports it, but IIRC the most common approach about testing just the kernel is to boot the new kernel over fastboot with fastboot boot <kernel>, instead of flashing a boot.img each time.

JBQ

Well I learn something new every day.   I looked at the fastboot code and it does indeed accept a kernel image or boot.img.  It determines if it's a boot.img by looking at the magic string of "ANDROID!" otherwise assumes it is a kernel image.   That little tip could have saved me some time....

BTW, "fastboot boot" only loads the image; it does not write to flash.  Test it and the run "fastboot flash boot..." which will write to the flash area.