[Nexus 4 Q&A, Help & Troubleshooting] Carpetboy:
So over the last week I've managed to solve my problem. I've seen several other people asking for help with no luck so I'm posting this here in the hope that the search function will bring it up.

Firstly, my phone was completely stock running 4.2.2, unrooted, with the locked stock bootloader. USB Debugging WAS NOT enabled. I had pattern lock enabled when I dropped the phone. The screen cracked and the bottom half of the touchscreen was unresponsive.

The phone was insured, but I wanted to backup photos from the device before sending it off for repair/replacement.

HOW I FIXED IT.

Please note, you need at least some part of the screen to be working, specifically, some part of the screen where the pattern lock is.

You only need two pieces of software. The Android SDK and the Nexus 4 Toolkit http://xdaforums.com/showthread.php?t=1995688

If you are running 4.2.2 you will need to update the toolkit. I also had the standard issues of installing the USB drivers for the N4. You need to get to a point where is shows up as an ADB device in Windows Device Manager.

As I didn't have USB debuggin enabled I couldn't connect tothe phone via ADB, but if you put it into recovery mode you can use Fastboot. Hold down the power key to turn the device off and turn it on while holding down Vol Down to load up recovery mode.

If you then start the N4 Toolkit, you should see the device listed as a fast boot device.

From within the toolkit unlock your bootloader.

Flash a temporary bootlader, (option 10) as the touchscreeen was broken it has to be CWM.

Once in CWM you can start to use ADB. Open up a DOS command prompt in Windows, go to your SDK/platform tools folder/ to access ADB.exe and you can use the pull command to copy folders to your PC. At this point, instead you can use applications like ADBexplorer or DroidExplorer to do the same thing through a nicer GUI.

If you'd like to still be able to use your phone, although without the touchscreen, you can load an unstable image to get into android and then use ADB to start changing system settings.

Firstly, before exiting CWM, clear the cache. Without doing this the phone jsut hung on the Nexus symbol while loading the image.

in the toolkit go to root/unroot options and select load unstable image(option 4 and then 6). This will fire you up into Android and it should be set up as you left it.

I wanted to enable bluetooth so to use a keyboard (I didn't have a mouse but this is a better option) from the DOS window type the following command

am start -a android.bluetooth.adapter.action.REQUEST_ENABLE

You should eventually get a pop-up on your screen saying that a request has been made to enable bluetooth. Hopefully your screen is working enough to select enable.

Then I use the workaround to disable the sceenlock, found here -> (http://www.addictivetips.com/androi...e-pattern-unlock-on-android-via-adb-commands/) I found method 2 worked for me. I imagine this will be stopped in a future update.

Method 1

adb shell

cd /data/data/com.android.providers.settings/databases

sqlite3 settings.db

update system set value=0 where name='lock_pattern_autolock';

update system set value=0 where name='lockscreen.lockedoutpermanently';

.quit

Method 2

adb shell rm /data/system/gesture.key

If either of these methods are successful you will be able to unlock the phone with an pattern, hence why you need to be able to touch some part of it.

From then, my bluetooth keyboard was already mated to my phone to I was able the navigate the menus to turn on USB Debugging, turn-off the screen lock and a few other bits and pieces I needed to do.

I then restarted (I was still working within the unstable image) and on reboot, all my changes had al been applied. No screen lock, bluetooth enabled and USB Debugging enabled.

Hopefully this will be of help to those in a similar position. Thanks has to go to the toolkit though which provides all the necessary access to carry this out.