Nexus 7 custom firmware

Although the Google Nexus 7 is pretty muck stock Android, I thought I’d give Cyanogenmod a try. Installing a custom firmware involves three steps – unlocking, installing a custom recovery mode, and installing the custom firmware. Oh and I’m doing this in Windows 7. There is also a very good guide on the Cyanogenmod Wiki which I followed. As I often do, this blog post is more to remind me what to do.

Setting up the tool chain

The Android Development Kit provides two useful tools – Android Debug Bridge (adb) lets you communicate with a connected Android device; and Fastboot which when in a boot loader allows flashing, erasing and rebooting. Once downloaded, unzip it to your folder of choice and add the sdk/platform-tools folder to your path (in Windows 7 you can do this by going to the folder in question, copying the address line and then right clicking My Computer→Properties→Advanced System Settings→Environment Variables, select Path and Edit then add the line with a leading semi-colon). The ADK requires the Google USB Driver and that you enable USB debugging (Settings→About and tapping “Build number” until Developer mode is enabled, then you can select USB debugging from Settings→Developer Options).

Unlocking the device

Connect the Nexus 7 via USB and open a command prompt in Administrator mode. Type:

adb reboot bootloader
fastboot oem unlock

The Nexus 7 will display a disclaimer – use the volume buttons to scroll through options and the power button to accept. Reboot the Nexus 7.

Custom recovery console

Turning the Nexus 7 on by holding down the volume up, volume down and power buttons. The stock recovery partition lets you do a factory reset but not much else so I replaced it with ClockworkMod which will install custom firmware and allow you to make backups.

First download the image, the Nexus 7 is available here. From the terminal:

adb reboot bootloader
fastboot devices

If there is no device listed, then you should check that the USB drivers are installed correctly. Ensure you’re in the correct folder and flash the Nexus 7:

fastboot flash recovery RECOVERY_FILE_NAME.img

Finally reboot into the new recovery image:

fastboot boot RECOVERY_FILE_NAME.img

Installing Cyanogenmod

Download Cyanogenmod – I choose the nightly build. You can also download Google apps here. ClockworkMod can install from SD card, which the Nexus 7 doesn’t have – but there is a folder called /sdcard/. From the terminal, use ADB to push the two files (obviously use the filenames you downloaded):

adb push cm-10.1-20130706-NIGHTLY-grouper.zip /sdcard/
adb push gapps-jb-20130706 /sdcard/

Now using the volume and power buttons to navigate the ClockworkMod menus:

  1. Back up the Nexus 7 (backup and restore→backup)
  2. Wipe data/factory reset
  3. Install the two zip files (install zip from sdcard→choose zip from sdcard)
  4. Reboot (reboot system now)

You should now have Cyanogenmod installed.