Updating the Nexus 5 to Adroid L

1. I needed to update the USB drivers and found them here:  http://developer.android.com/sdk/win-usb.html -- without it, the phone would not work with adb / fastboot
2. adb reboot-bootloader (reboots your phone into fastboot mode -- works if #1 works!)
3. fastboot devices (shows you the phone connected hopefully if #1 works!)
4. fastboot oem unlock (as the device is locked by default -- )
1. Funnily, or maybe not, it deletes everything on the phone when you chose this option
2. For reference, it took 45 seconds to wipe my Nexus 

C:\Users\sd>fastboot oem unlock
...
OKAY [ 45.840s]
finished. total time: 45.847s

If you want some photos, check out this page:  http://www.droid-life.com/2013/11/04/how-to-unlock-the-nexus-5-bootloader/

1. Go to the folder where you have extracted / downloaded Android "L" 
2. Run:  flash-all
3. Here is the output I had

sending 'bootloader' (2508 KB)...
OKAY [  0.326s]
writing 'bootloader'...
OKAY [  0.467s]
finished. total time: 0.806s
rebooting into bootloader...
OKAY [  0.087s]
finished. total time: 0.093s
sending 'radio' (45505 KB)...
OKAY [  2.036s]
writing 'radio'...
OKAY [  3.107s]
finished. total time: 5.160s
rebooting into bootloader...
OKAY [  0.080s]
finished. total time: 0.086s
archive does not contain 'boot.sig'
archive does not contain 'recovery.sig'
archive does not contain 'system.sig'
archive does not contain 'tos.img'
Creating filesystem with parameters:
    Size: 29236371456
    Block size: 4096
    Blocks per group: 32768
    Inodes per group: 8192
    Inode size: 256
    Journal blocks: 32768
    Label:
    Blocks: 7137786
    Block groups: 218
    Reserved block group size: 1024
Created filesystem with 11/1785856 inodes and 156120/7137786 blocks
Creating filesystem with parameters:
    Size: 734003200
    Block size: 4096
    Blocks per group: 32768
    Inodes per group: 7472
    Inode size: 256
    Journal blocks: 2800
    Label:
    Blocks: 179200
    Block groups: 6
    Reserved block group size: 47
Created filesystem with 11/44832 inodes and 5813/179200 blocks
--------------------------------------------
Bootloader Version...: HHZ11k
Baseband Version.....: M8974A-2.0.50.2.08
Serial Number........: XXXXXXXXXXXXXXXXXXXX
--------------------------------------------
checking product...
OKAY [  0.100s]
checking version-bootloader...
OKAY [  0.079s]
checking version-baseband...
OKAY [  0.093s]
sending 'boot' (8754 KB)...
OKAY [  0.536s]
writing 'boot'...
OKAY [  0.750s]
sending 'recovery' (9412 KB)...
OKAY [  0.643s]
writing 'recovery'...
OKAY [  0.781s]
erasing 'system'...
OKAY [  1.311s]
sending 'system' (683564 KB)...
OKAY [ 27.972s]
writing 'system'...
OKAY [ 46.692s]
erasing 'userdata'...
OKAY [ 15.515s]
sending 'userdata' (139109 KB)...
OKAY [  5.937s]
writing 'userdata'...
OKAY [  9.362s]
erasing 'cache'...
OKAY [  0.485s]
sending 'cache' (13348 KB)...
OKAY [  0.756s]
writing 'cache'...
OKAY [  1.069s]
rebooting...
finished. total time: 115.481s

That's it -- cool, eh?

What's changed?  Well, after the android dude disappears (after install completes), the android colours/balls go flying in a crazy pattern on the boot screen animation.  no clue how long this goes for...