Timur's Kernel for Nexus 7 2013 (2nd gen)

Like it's predecessor for the 1st gen Nexus 7, this new kernel for Nexus 7 2013 with stock Android offers extended features for power management and USB Host-mode support.

New: Kernel v4.0 for Nexus 7 2013 + Android 6.0.1


USB Host + charging

This feature allows you to connect one or more USB slave devices to your tablet and charge it at the same time. This allows you, say, to operate an external USB DAC without the tablet ever running out of power. To use this feature you will need an "OTG charging" - or a std. OTG adapter combined with a USB-Y cable.

Fast Charging

By default, USB devices limit themselves to a 500 mA charge, which is intended to protect (not overload) the hub and the power supply. By directly connecting the N7 to it's own power supply, the power supply will short the (otherwise unused) USB data wires and this way signal it's presence to the tablet. The tablet will take advantage of this and will start to fast charge. In fast charge mode it will fetch up to 1400 mA and will display "charging (AC)" on the battery pane. In USB host mode, the data wires are being used for data communication.

But when using Timur's kernel, one can enable fast charging in USB host mode by the flip of a switch. This will tell the tablet, that it is OK for it to fetch more than 500 mA (and up to 1500 mA) from the attached power supply. Fast charging will generally charge your tablet much faster. And no matter what you do with it (full brightness, high CPU/GPU usage, etc.), it will likely just stay at 100% charge.

Fixed Installation mode

In FI-mode, your tablet will go to deep sleep, when the external power supply is interrupted. Your tablet will stay in suspend mode and will immediately wake up, when external power returns. FI-mode is particularly useful, if you don't have direct access to the tablet's physical power button.

Firm Sleep

Firm Sleep allows you to disable all wake-up alarms while your tablet is in deep sleep mode. This way, a fully charged Nexus 7 can stay in sleep mode for many weeks - much longer than it usually would. Alarms allow apps to wake your device from deep sleep, for instance to implement an alarm clock or to periodically fetch mail. Apps also wake your device from sleep to check for updates etc. Wakeup alarms make a lot of sense on phones and tablets. But probably not so much in a fixed install scenario. This is why you should always enable Firm Sleep in FI mode.

USB Audio on boot

With stock Android, even if USB Audio is supported, it won't work if you boot your table with your USB DAC connected. Timur's kernel solves this issue, so no matter if you connect your DAC manually after rebooting, or whether you reboot with your USB DAC attached, your DAC will always be used for audio playback.

Other v1.0 features

- Auto-mounting flash drives (FAT32).
- Ability to execute /data/local/userinit.sh (like autoexec.bat).

Version v2.0

Ability to integrate a power-down video:

Ability to block rtc alarms for individual apps. Blocking rtc alarms can greatly reduce battery drain in suspend mode. (Similar to how Doze works on Android 6.)

Loadable kernel driver support + working driver for EasyCap Syntek STK1160 frame grabber.

Event based custom shell script execution. This allows you, for instance, to automatically kill specific processes before going to suspend.

Version v3.0

USB host-mode charging kernel for Android 5

Auto-Cam support - For use as rear camera. Comes with VCam app. No 3rd party software required. EasyCap Syntek STK1160 driver integrated in kernel for plug&play use. Works out of the box. Multiple ways to auto-trigger camera view.

Note: Today (Feb. 12. 2016), more than two years after this project has started, it has become difficult to purchase compatible EasyCap Syntek STK1160 frame grabber devices. Alternatively, UVC campatible devices can be used. Android supports UVC devices natively. No kernel drivers need to be installed to operate UVC devices. VCam app provides identical support for Easycap Syntek STK1160 and UVC devices.

Live USB Device Monitor

Better Power Event Manager

Live Charging Monitor

v3.0 beta R3 for Nexus 7 2013

- Support for Android 5.0.2: flo + deb.
- Available Feb. 19, 2015.
- Double-tap to wake screen.
- Auto-mounting of up to 4 drives (with up to 2TB each).
- Drive-label based mounting to preferred mountingpoint (drives will re-mount to the same spot, despite file locking issues, etc.)
- Media Server support (auto-runs on mount/unmount).
- UTF8 mounting with support for umlautes in filenames.

Q: Why is this not a full ROM?

A: This software consists of a modified kernel, a threadless event handler, a small number of Android services modifications, and some runnable activities.

It would have been possible to take the stock AOSP, bundle it with the modified kernel and the other modified code, packaging everything up and distribute a big, self-contained binary. We would call this a ROM. A ROM replaces all parts of the existing OS on a device.

But this software does not come packaged with the full Android code base. Instead, the installer files only contains the actual changes. To make this work, I am asking you to install Timur's Kernel on top of a specific version of Android. Once the two parts have been combined on the target device, the outcome is essentially a ROM.

By using a modular distribution method, the installation files can stay small and handy. But note, that the changes are still very much tied to one specific version of Android.

When you install Timur's Kernel, most areas of Android are not being touched. For instance, the LTE, Wifi and Bluetooth subsystems (just to name a few) do not get modified at all. With a full ROM, it is not possible to tell, what areas of the OS have been modified.

v3.0 beta R4 for Nexus 7 2013

- Support for Android 5.1.0 (flo + deb).
- Available June 2, 2015.
- PAL + NTSC rear-camera support.
- On-power CPU Governor.
- USB device permission dialogs fully disabled.
- PL2303 kernel driver support.
- New, faster Easycap drivers.

v3.0 beta R5 for Nexus 7 2013

- Support for Android 5.1.1 (flo + deb).
- Available June 19, 2015.
- Full power off + wake-on-power support.
- New post-suspend battery stats:

v3.0 beta R6 for Nexus 7 2013

- Support for Android 5.1.1 (flo + deb):
  LMY47V, LMY48G, LMY48I ("Stagefright" fix),
  LMY48M and LMY48P.
- Very low battery drain while in suspend: 2% or less
  over 12 hrs.
- Improved anti-cranking protection.
- Improved wake-from-sleep processing.
- Fixes USBDevice GetInterfaceCount()=0 bug.
- Removes USB device permission dialogs.
- Available: August 26, 2015.

v3.0 beta R7 for Nexus 7 2013

- Support for Android 5.1.1 factory images LMY48M, LMY48P, LMY48T and LMY48U. These are the latest Android 5.1.1 variants from September and October 2015 (flo and deb).
- Several minor bugs fixes.
- Available: October 12. 2015.