Fixing adb "Device not found" with Nexus 7/Android devices in Recovery Mode
I'm a huge fan of the Nexus 7, but one of the things that annoyed me from day one was the lack of landscape support on the homescreen. I almost always use the tablet in landscape mode, so when switching to an app I didn't already have in the open/recent apps list, I would have to hit the Home button; which flipped everything around temporarily. There was already a user-set orientation lock, and we knew Android could handle it (from other devices, and those with rooted devices changing build properties), so it always seemed like a really random restriction.
This was announced as fixed in Android 4.1.2, which began rolling out only a few days ago. As of this evening, my device still showed no update, so after finding some instructions, I decided to load the update myself.
These instructions do *not* require you to root your device or unlock the bootloader. If your device is unlocked/rooted, I have no idea what affect that might have on this process. If you're unsure about this, don't do it. I accept no liability if you mess things up. I have only limited knowledge of Android! The steps seemed fairly straight forward, which is the only reason I was attempting them!
My first problem was that I was unable to boot into recovery mode using the instructions. When I selected Recovery Mode from the boot menu, my device just booted normally. I didn't get the Android with the red exclamation mark. This was easily fixed by using adb (installed as part of the Android SDK) and running:
adb reboot recovery
This rebooted the device to the screen showing an Android with a red exclamation mark, and pressing Power + Up allowed me to select the "Update from ADB" option.
The problem was, once in this mode, Windows failed to recognise the decide/load the drivers that were previously loaded (before the reboot), which meant adb would no longer be able to connect the device:
adb: device not found
After a lot of searching online, I figured out that the problem was that the Hardware ID of my Nexus 7 when in recovery mode was not listed in "android_winusb.inf" file from the Google Android Windows USB Drivers. The ID I saw in device manager against the Nexus was USB\VID_18D1&PID_D001, which didn't turn a lot up in Google!
I decided to try adding this to the inf file manually (C:\Program Files (x86)\Android\android-sdk\extras\google\usb_driver\android_winusb.inf). As I'm running on a 64bit machine, I added the following to the [Google.NTamd64] section (note: this applies to Intel 64 bit machines, not just AMDs!). If you're using 32bit, you'd want to add it to the [Google.NTx86] section:
[Google.NTamd64] ; !-- snip other devices... --! ; Google Nexus 7 ; !-- snip existing device IDs --! ; This is the HardwareID shown in Device Manager for the "Nexus" ; device when in Recovery mode %CompositeAdbInterface% = USB_Install, USB\VID_18D1&PID_D001
After making this change, I uninstalled the device drivers, then reinstalled them using this inf file. I once again rebooted into Recovery mode, and this time, Windows correctly displayed the device as "Android ADB Interface", and I was then able to sideload the Android 4.1.2 update (downloaded directly from Google) by typing:
adb sideload 03a4eaf95f73.signed-nakasi-JZO54K-from-JRO03D.03a4eaf9.zip
ADB transmitted the file to the Nexus 7, then the Nexus spat out the progress as it verified the image and updated the device. A reboot later, and my Nexus 7 was running Android 4.1.2!