postmarketOS

asus grouper (Google Nexus 7 2012)

Contributors

• antonok

What works

• Boot process
• Telnet/SSH over USB
• Screen
• USB keyboard, mouse
• Touchscreen

What does not work

• weston-keyboard
• Wifi + other untested parts

How to enter flash mode

• Connect a USB cable
• Power the device off
• Hold power + volume down
• fastboot should work when the green android appears on the screen

Notes

• I am using the LineageOS kernel found here
• The kernel cannot be compiled on versions of gcc newer than 4.9 without a patch, found here
• I could not get UART debugging through the headphone jack to work - as far as I can tell, the 2012 version of the Nexus 7 does not have this feature.
• CONFIG_VT had to be enabled for graphics to work. In menuconfig this is located under Device Drivers -> Character devices -> Virtual terminal.
• /sys/class/graphics/fb0/mode is empty on boot, it must have U:800x1280p-0. This uses the same initfs hook as many other devices.
• xwayland does not work.
• weston with fbdev-backend.so uses pixman-type=3 (PIXMAN_TYPE_ABGR), which now does not require configuration.
• The touchscreen input device is named elan-touchscreen.
• The wifi chip is the Broadcom 4330.
• This device was once officially supported on Ubuntu, so it has a firmware package in the Ubuntu repositories.

Image

Fun fact: grouper is the first tablet to run pmOS!