• Announcements

    • PaulOBrien

      Reminder - MoDaCo position on illegal content   07/30/15

      ILLEGAL CONTENT I'd like to just reaffirm MoDaCo's position regarding piracy and illegal content in the light of some recent questions / postings. Posts will be censored by myself or my moderation team if the contain or link to: Illegal / pirated / cracked software or sites that host such software Nintendo emulators / ROMs or sites hosting them (in light of Nintendo's legal stance) CUSTOM ROMS You may discuss and post links to custom device ROMs on MoDaCo, provided the following rules are adhered to: ROMs must not contain any illegal 3rd party software (this includes trial versions included without permission) ROMs must give full credit to the original author ISSUES If you have any issues with this policy, please contact PaulOBrien directly via PM.
    • PaulOBrien

      Reminder: Selling items on the forum directly is not allowed   07/30/15

      Please note that selling items on the forum directly is not allowed by the forum rules. There is a forum for eBay auctions whereby you can list the items on eBay and link to them there. This is the ONLY forum for this type of activity. You may also advertise links to the eBay forum in your signature. Please note that selling directly in contravention of these rules will result in a warning / suspension / ban.

How to compile your own Android kernel in linux

4 posts in this topic

First you need an original boot.img file. Extract its components

with the abootimg program.

$ abootimg -x boot.img

writing boot image config in bootimg.cfg

extracting kernel in zImage

extracting ramdisk in initrd.img

Search for the first "1F 8B 08" bytes in zImage (that's the

signature of a gzip file); make a new file starting from there

and gunzip it. This will create your Image kernel (decompressed)

In the new file search again "1F 8B 08" and make a new file out

of that and gunzip it. This will be your kernel config file.

Alternatively you can do 'zcat /proc/config.gz' on your runnig

phone to achieve the same result. For convinience I've already

edited out the CONFIG_ACER_SECURE_MOUNT define and you can

grab the file here.

Install your ARM cross-compiler and toolchain from your favorite place.

grab the kernel sources opensrc_Acer_AV051_S500_RV04RC09_WW_GEN1-20130322.tar.gz

or newer; untargz them. Edit the file ./drivers/gpu/msm/adreno.c and change

in function adreno_iommu_setstate the 'unsigned int link[250];' to 240

otherwise you'll have a frame overflow error.

Also in scripts/Makefile.lib change this line (if you want)

-cmd_gzip = (cat $(filter-out FORCE,$^) | gzip -n -f -9 > $@) || \

+cmd_gzip = (cat $(filter-out FORCE,$^) | 7z a $@ -tgzip -mx=9 -si) || \

because the 7z can also make gzip files but with much better compression.

Finally after you've copied the '.config' in the kernel tree

$ make ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- zImage

... and wait. After a while you'll have yout new zImage file.

Now the ramdisk: make a 'work' directory and cd to it.

$ zcat ../initrd.img | cpio -i

edit the default.prop file to 'ro.secure=0' and 'ro.debuggable=1'

and then convert back to compressed cpio:

$ find . ! -name "." | cpio -o -H newc | 7z a ../initrd.img -tgzip -mx=9 -si

now 'cd ..' and put everything back together

$ abootimg --create boot.img -k zImage -r initrd.img

look at the new size of your boot.img modify in bootimg.cfg the bootsize

value (in hex) to reflect this new size and run again with the -f parameter

$ abootimg --create boot.img -f bootimg.cfg -k zImage -r initrd.img

Done. Here is my compiled version.

Edited by zelea2

Share this post

Link to post
Share on other sites

So this is a kernel ? Mount RW/RO works with this kernel ? What this kernel contains ? What gouvernors? And what did you modified ?


Share this post

Link to post
Share on other sites

Thanks for your tutorial zelea2!! It helped me a lot with building my own kernel. I did a few things in an alternative way:

In adb shell on the device I did:

cat /proc/config.gz > /external_sd/config.gz
Then in shell I did:
adb pull /external_sd/config.gz[/code]

to transfer the file to the current directory. Then I did a 
[code]gunzip config.gz[/code]
to unzip the config file. After modifying the config file (just modified the CONFIG_ACER_SECURE_MOUNT from n to y) I build the kernel. I did not modify anything else!! I did get an error while repacking the ramdisk when using your command. To succesfully repack I used
[code]find . | cpio -o -H newc | gzip > ../initrd.img[/code]
After creating a boot.img it runs perfectly. I get the same benchmark results with my own compiled kernel as with the original (even slightly better!) What do you mean with the frame overflow buffer? Without modification my kernel seems to run fine or am I missing something? Do you also know how I can make the S500 let accept a
[CODE]adb remount[/code]


Thanks in advance!

Edited by bobbes

Share this post

Link to post
Share on other sites

Would it be unwise to change other stuff in the build.prop? I'm thinking things like lcd density ( value up or down?),

acer shell, ...


Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

MoDaCo is part of the MoDaCo.network, © Paul O'Brien 2002-2016. MoDaCo uses IntelliTxt technology.