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
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
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:
- Back up the Nexus 7 (backup and restore→backup)
- Wipe data/factory reset
- Install the two zip files (install zip from sdcard→choose zip from sdcard)
- Reboot (reboot system now)
You should now have Cyanogenmod installed.