If your Glass is experiencing the XE16.1 boot loop, you can recover from it by re-flashing the factory system image from https://developers.google.com/glass/tools-downloads/system
This technique requires you to use the Android tool, fastboot, and I'm told it only works on OSX or Linux.
Here are the instructions:
Download and install the Android development tools from http://developer.android.com/tools/index.html
You'll find the fastboot application in your platform-tools subdirectory of the Android development tools main directory.
Next, download the Glass system factory image from https://developers.google.com/glass/tools-downloads/system
and unzip the files into a sub-directory. You'll want to run fastboot from that subdirectory.
Now, power off your Glass by holding the power button for 15 seconds.
Put your Glass in fastboot mode: while holding the camera button, press the power button as you would to turn it on. Keep holding the camera button until the power light comes on and then pulses every 4 seconds.
Now connect Glass to your computer via its USB cable. Verify Glass is in fastboot mode and detected by your computer using the command:
You should get a response like:
if you get
then wait a couple seconds and run the command again until you get a response with your device's ID number.
Next, unlock Glass. You'll need to run the following command twice. The first time you'll get a warning about voiding your warranty. If you're worried about this, contact Glass Support and they'll help you do this and absolve you of any wrong doings. :-)
fastboot oem unlock
fastboot oem unlock
You should get a message saying that it's erasing personal data, erasing cache, and unlocking. It will probably hang after that. Don't panic. Give it about 5 minutes and then power it off and power it back into fastboot mode like you did before.
Now you should be in fastboot mode and unlocked. Check that it's connected again by using the command:
If you are, execute the following commands in the directory where you unzipped your system images:
fastboot flash boot boot.img
fastboot flash recovery recovery.img
fastboot flash system system.img
The last one will take a few minutes because it's a big image.
Now clear your userdata, cache, relock Glass, and reboot:
fastboot erase userdata
fastboot erase cache
fastboot oem lock
Your Glass should now reboot without the boot loop. Mine seemed to hang initially on the "GLASS" screen and I powered it off and then back on. Eventually I got the message "Glass is updating" and then the "Welcome to Glass" screen.
Finally, just follow the on-screen prompts to setup your Glass.