UPDATE/EDIT: Courtesy of umataro42, keep in mind this only applies if you're flashing a factory image, "Forgot to mention this on Friday, but if you're going to flash 5.0 on your Nexus 5, and you have 2 factor authentication set up for your Google accounts, and you're set up to receive the code by text, and you plan to do a data wipe (which is usually recommended when going from one build of Android to another like from KitKat to Lollipop), make sure you have some printed out 2-Factor codes. You can also set up an app like Authy, which also allows access to the codes from a PC.
Because on the Nexus 5, the default messenger is Hangouts, which requires you to be signed into Google, which will require a 2FA code, which will be sent to Hangouts as an SMS, which you won't be able to access without the very same 2FA code. So you will want to have a printed out code, or if you're using Authy, you can just generate it on your PC (or another device since they can be synced up)."
EDIT: Just want to reiterate that only applies if you're flashing a factory image. If you're sideloading an update you have nothing to worry about. As long as you're originally signed in, which almost all of you who don't tinker regularly should be, then you'll experience no issues when you sideload the update. I can vouch for that myself, since it's the path I underwent when I sideloaded the update on my 2014 Moto X going from Kit Kat (4.4.4) to Lollipop (5.0).
So Lollipop is now official and numerous devices are currently receiving the update to the latest version of Android. This is the post where I'll share everything that is currently out there for a number of devices.
I'm including links to the OTA updates for several Nexus devices, as well as links to the factory images (all where available, if they are at all) and I'm going to include a few instructions as well so you can get those loaded up easily enough.
Now, before I do that I want to state three things.
1. If you do not have ADB or fastboot setup on your computer then you need to do that first before you can do any of this stuff. I've worked with ADB and fastboot solely on Windows computers, so if you've got something else running something else you'll need to do the research on your own to get setup.
2. Assuming you aren't already setup, you can go here to get what you need to do that. Myr ecommendation is to get Version 1.4.2 (and get it from the Dropbox or Google Drive link, as the other one is not currently working).
The install process for that is as follows.
1. Run it (Require administrator privileges)
2. Press Y/Yes to install ADB and Fastboot or N/No to skip
3. Press Y/Yes to install ADB system-wide or N/No for current user only
4. Press Y/Yes to install Drivers or N/No to skip
5. Continue Driver installation
6. 15 seconds passed - finished!
3. If you aren't at all familiar with ADB, fastboot, manually flashing OTA updates or factory images then you can do one of two things. Stop reading here or continue on and if you feel adventurous but unsure feel free to say so in the comments and I'll help you as best I can. Keep in mind apparently I am going to be crazy busy today at work, they're piling stuff up for me to do on a rather lengthy run here in a bit, so I might not be able to respond as quickly as normal. I'll get to your comments and questions when I can, otherwise there are quite a few people on here (umataro42, Pessimippopotamus, ShadowStaarr, nctrns and a cat named scruffy live from Caldor being the ones I immediately think of) who can also help you out. Every single one of those people has done any/all of the things you'll read about from here out, along with myself, and it goes without saying that they've done it more than once and know it like the back of their hand at this point.
Additionally, for the OTA update zips at least, you need to make sure you're on the correct version of Android (specifically the build) to make sure the OTA update zip sideloads correctly. Otherwise you'll see an error and it won't install. You can find your Build Number by going to Settings then About Phone and scrolling all the way to the bottom.
So to give you an idea of what's going to happen, assuming you have any of the devices below, you're going to download the update to your computer. You are then going to make sure you have USB debugging enabled (I'll explain how to do that in a bit), you are then going to run the command to put you in recovery and from there you will run the command to sideload (and install) the latest update to put you on Lollipop. Easy peasy.
Nexus devices OTA Updates
Nexus 5. There are two for this device, one to take you from the KTU84P build of Kit Kat to Lollipop and one to take you from the KTU84Q build of Kit Kat to Lollipop. If you're version of Android is KTU84P then grab your update here. If you're version of Android (build number) is KTU84Q then grab your update here.
Nexus 7 2013 (WiFi). This one takes you from a build number of KTU84P to Lollipop. You can grab it here.
Nexus 7 2012 (WiFi). This one takes you from a build number of KTU84P to Lollipop. You can grab it here.
Ars Technica did a wonderful little write-up on the Nexus 7 2012 and running Lollipop on it, which you can read here.
Nexus 10. This one takes you from a build number of KTU84P to Lollipop. You can grab it here.
Moto X 2014. This takes you from Kit Kat (4.4.4) to Lollipop. You can grab it from here, courtesy of SolarsTrans over on the XDA Developer Forums (who shared it with the community). It's the item on the left in that link by the way.
And that's it as far as OTA update links goes. I'll update (and link to) the post when additional links are shared by the Android enthusiast community.
Moving on we get to the Factory Images for Lollipop from Google. Again, keep in mind this are just download links, the fun stuff will come further down where I explain how to flash these.
Nexus Device Factory Images
Nexus 5. You can grab the Lollipop factory image from here.
Nexus 7 2013 (WiFi). You can grab the Lollipop factory image from here.
Nexus 10. You can grab the Lollipop factory image from here.
Nexus 7 2012 (WiFi). You can grab the Lollipop factory image from here.
Nexus 4. You can grab the Lollipop factory image from here
And that is that as far as Factory Images are concerned. Now we move on to the fun part! Installing Lollipop!
So now we get to the good stuff, ADB and fastboot!
First off, before we dive into any of these things you need to setup your device to be read by ADB and fastboot.
To do this, go into your phone/tablet's Settings. Scroll down to About Phone and click that. Then scroll all the way down to Build Number, click on that 7 times. You'll eventually see a message saying "you are now a developer".
Once you've done that, go out one page and you should see a new option saying Developer Options.
Go into that and first off turn on Developer Options if it isn't already activated. Then look for USB Debugging and enable it. A message will appear, click okay on it.
If you're still with me at this point, you're all set for tinkering from your device's perspective. Mostly.
If you haven't setup ADB/fastboot already go ahead and do that. Grab what you need from here. (That's that link to the 15 Seconds ADB Installer v1.4.2 page on XDA from way above.)
Run that and get it setup.
Now, you're still not done. Now you need to test if everything is working correctly. Plug your phone into your computer at this point. Wait a few moments, a message should pop up on your phone/tablet . You're going to check off "Always allow from this computer" and then click OK.
Now you're officially ready as far as your device is concerned. But let's do one last check before we get into anything.
Remember that zip file we downloaded for your device earlier? I want you to do something with it.
Go to your desktop and create a new folder, call it "Android Tinkering" for the sake of amusement. Drop that zip file in there.
Now, press the Shift Key on your keyboard and right click with your mouse anywhere inside said folder. You'll see a few options, the one you want is "Open command window here". Click it. You should see a Command Prompt window appear at that point.
Here's where we test to make sure your device is communicating with your computer. Plug it into your computer using a microUSB cable. Once you've done that run the following command in that Command Prompt window.
Type that in and hit enter. You should see a few lines of text appear about a daemon and then the command itself will actually running. You should see something something like what you see below.
More specifically, your devices exact serial number and either the word device or more specifically its exact model type.
As long as you see those two things there then you're good to go.
So you're now ready for the "hard" part. Sideloading the OTA update zip from wayyyy above.
How to sideload an OTA update
Updating via sideload does nothing to your device itself. So all your stuff is safe and there when the update is complete. Just FYI. Getting that out of the way before we proceed.
Let's assume you're all setup by this point and that you closed that command prompt window.
In the folder where you stored that zip, press the Shift Key again and right click with your mouse. Then select Open a command window here.
Once you've done that run that command we did again, just to be sure everything's fine.
When you see that everything is working correctly you're going to run another command.
adb reboot recovery
At this point your device should shut off and reboot into recovery.
Now, using your Volume keys you're going to scroll to the one that says "apply update from ADB", select it by pressing the Power button on your device. At which point you'll see a message at the bottom.
It is at that point we go back to your computer and we run the fun command that makes the magic happen.
Now that update zip likely has some ridiculously long name. For the sake of simplicity, rename that file "lollipop-update" minus the quotation marks. Then run the following command in that command prompt window.
adb sideload lollipop-update.zip
You'll see it run and it'll say sending. Once it's done sending you can stop paying attention to your computer and pay attention to your device.
It'll receive the zip file and then proceed with installing it and running all the commands within that it needs to get it setup properly.
Once it finishes, it'll say as much. At that point, using the Volume keys again navigate to "reboot system now". Hit that Power button and get ready for the magic to appear on your screen, cause you now have Lolipop and it should boot up fine. (Minus optimizing apps, which can take a bit.)
Congrats! You've just completed your first ADB sideload of an OTA update! Who rocks? You do!
Now, if anyone wants to know how to flash a factory image file please say so. I won't post the instructions for that since it requires unlocking your bootloader (which is needed to do this) and that will wipe everything on your device. Don't want people to just go off flashing things and then say "Where's my stuff?! What did you do to my stuff, you monster?!"
So like I said, if you want to do things that way say so and I'll update the post with the necessary instructions.
And before anyone chimes in with "but there are already tons of websites detailing how to do all this" I'd just like to point out not everyone who reads these posts knows about those sites or how to do all that. Sometimes the instructions, in my opinion, are far more complicated and in some cases not as clear than they should or need to be. I write these posts with people who are new to all this in mind. Keeping things as simple as possible for their sake while also teaching them some stuff they might not know.
And on that note I'm gonna do some pre-lunch redditing! Hope you all learned something from this even if you didn't undertake the journey yourself into sideloading an update.
Everyone have a great and safe weekend! I'll be here til 4:30 PM CST answering questions or responding to comments, after that I'm pretty much MIA until Monday morning.