A (165)

Hacker Zøne

Flash a modified

boot image for

Lollipop root

Rooting dev ices is more complex

on Lollipop than on KitKat

because it now requires use of a

custom boot image

Nexus devices will generally have a

selection of custom kernels available. The best

place to look is the Original Android Development

forum for your device at XDA-Developers.com.

Look for kernels uploaded by respected

developers such as faux123, fl ar2 or Franco.

In order to root your device, you need to
download the rooted boot image. Community
hacker Chainfi reXDA has images available with
the name CFAutoRoot. Head on over to http://
autoroot.chainfi re.eu to download it.

The downloaded image ZIP will contain script
fi les to root your device for Windows, Mac and
Linux. Note that running these will wipe your
data if you are not already bootloader unlocked!

Get custom kernels

Download a rooted boot

image for your Nexus

Flash the rooted boot

image ZIP

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OTA updates will often either fail to
apply on rooted devices or unroot as part of the
update process. Don’t worry if you do end up
being unrooted because you can just rerun the
script after updating.

Beware of OTA updates

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A good way to reduce the device

temperature (which will also improve battery life) is

by throttling the CPU and GPU clocks. This is best

achieved using a kernel companion app if

available. Change the values in small increments

to fi nd your own optimum settings.

Adjust CPU/GPU clocks

Many custom kernels have companion^4

apps available from the Play Store, such as franco.

Kernel updater for Franco’s kernels. Companion

apps help you stay up to date with the latest

releases and also tweak the settings of the kernel

itself, giving a far greater degree of control.

Install the companion app

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Kernels are contained within a boot image

and can either be flashed from bootloader using

‘fastboot fl ash boot fi lename.img’ or booted for a

one-time try using ‘fastboot boot fi lename.img’. If

you’ve decrypted your device, make sure you

custom kernel is set to decrypted mode too!

Flashthecustomkernel

2

T

he Nexus 9 has a very powerful processor – a 64-bit Nvidia K1 with 192 graphics cores.

This power makes for great experiences, especially gaming, but the dev ice does get

warm in the top-left corner. The source code for the Nexus 6 kernel source is available

from the AOSP repositor y, and a number of respected communit y developers have already

released custom kernels which tweak settings to let the system run cooler without affecting

performance. They also offer a number of other enhancements controlled by kernel

companion apps. The kernel is fl ashed to a dev ice as part of the boot image.

The Nexus 9 gets warm during use – an optimised kernel

can help reduce the temperature

Cool your Nexus 9

with a kernel