Nexus升级Android N需要注册Google的测试版计划https://www.google.com/android/beta，但我的Nexus 6P注册时显示 “Unfortunately, there are no eligible devices associated with this Google account”，手机没有root，Google账号登陆，且是最新的棉花糖系统。解决办法如下
转自http://www.androidpolice.com/2016/03/10/the-android-beta-page-is-now-up-and-running/这里的一个回答。
- How to Fix for ‘Unfortunately, there are no eligible devices associated with this Google account‘
Step 1: CHECK/SELECT Android Device Manager at Settings->Security->device administrators.
Step 2: goto Settings>Google>Security>Android Device Manager and UNCHECK Allow Remote lock and erase.
Step 3: Goto Settings->Apps->All->Google Play Services-> storage>manage space>clear all data. This action does not clear your personal data.
Step 4: Goto back Settings>Google>Security>Android Device Manager and CHECK Allow Remote lock and erase.
Step 5: Restart your device.
Step 6: wait for few minutes and goto https://www.google.com/android... and your nexus device should be seen now. if not, make sure to CHECK/SELECT your nexus device in https://play.google.com/settin... ‘show in menu‘