I recently became the owner of Asus's ZenPad S Z580CA. I chose this device as my new tablet because of many factors:
- Size: it is so thin and light
- Performance: an Intel x86 CPU matched with 4GB of RAM should have no problems in most situations
- Screen: the 4:3 aspect ratio is excellent for a tablet.
- Price: At only 9000NTD, it is priced the same as the 2012 Nexus 7
All things considered, this should have been a relatively painless investment. After all, with today's standards, how bad could a premium tablet really be? It turns out that Asus engineering still leaves something to be desired.
The main problem I ran into with the tablet was battery life. It's not bad by any means, but there is a huge wakelock caused by Android OS every night after charging.
And try as I might, I cannot find the source of the wakelock, even using BetterBatteryStats. It just doesn't show up as a partial or even kernel wakelock.. I even used AppOps to disable the "Keep awake" permission of the Android System. But that obviously didn't solve the problem.
Digging further, I read that this issue may be related to Android 5.0 and x86 devices. Android is built for ARM, not x86. And to make matters worse, my tablet uses a 64 bit x86 CPU. The only solution was to reboot every morning.
I couldn't take the bad battery life anymore. I decided to flash Xposed (which is in alpha for Android Lollipop+) and install Amplify. The first problem with that was I could no longer turn on WiFi. My SD card also could not be recognized. So I flashed the Xposed uninstaller. It still didn't work. I did a factory reset. Still nothing. It seemed I would have to send it in for repair. But then I thought: the tablet seems a bit hot. I shut it down and put it next to a fan for 5 minutes. Then I booted it. Everything worked normally. *facepalm*
So here I am now. I have a premium Asus tablet that is crippled by appalling wakelocks every night. Asus doesn't seem to care (I sent a message to customer service with no answer). It's rather unfortunate that Asus is abandoning their high end devices. I suppose that my next steps to solve this problem will be to install PowerNap, and if that doesn't work, I'll set an automated task to reboot after charging...