doing the adb sideload OTA for Nexus 7 2013 Wifi right now (
http://www.androidpolice.com/2014/11/13/flash-all-the-things-lollipop-ota-update-zip-file-roundup/)
after wasting an hour let me give anyone else doing this for the first time (in a while) a heads up (Win8.1):
1) if the Android SDK Manager won't run, you need to install java
(doesn't say that, it just closes leaving you wondering WTF is going on)
After fixing that and correctly installing the SDK Tools, SDK Platform-tools & Google USB driver using the SDK manager, you might encounter the following issues
2) if the ADB command doesn't work in a command window, you need to add C:\Android\sdk\platform-tools and C:\Android\sdk\tools to the "PATH" variable in Windows Environment Variables
(why can't the SDK do this?)
3) if the ADB command now works but can't find your connected tablet/phone, the USB driver probably isn't installed correctly. I had to force install the USB driver in C:\Android\sdk\extras\google\usb_driver as "Android ADB Interface" (this was with the tablet connected in the "load update from ADB" mode)
(why is the Device ID when in fastboot not in the driver.inf?)
done after about 15 minutes? everything seems to work fine, no wipe needed obviously