Arch Linux on Nexus 7 Flo Native

Here are my instructions on getting Arch Linux ARM natively booting on the Nexus 7 Flo. Ideally this would be booting from a usb stick or a dedicated partition on the mmc but this is working for me now.

BUGS!!!

There is no frambuffer console :( If you cannot get it booting you will need to reboot into recovery and check /proc/last_kmsg for the errors. Or try and build the UART cable (which I failed at)

The Software Refresher in the kernel does not work. You will need to run my refresher app or fix the kernel :)

The new xa code from x86-video-freedreno-git does not work. gpuaddr in kgsl_bo_gpuaddr comes back a 0

Quick Guide

1: I roughly followed the instructions form https://github.com/borh/nexus-7-2013-arch-scripts to get a working chroot first.

1a: remove trimslice packages from chroot

2: Edit the init script to point to your arch.img or partition

3: Edit and Run makebootimage.sh

4: fastboot boot newboot

5: ???

6: Profit

To get WiFi Working

A normal Nexus 7 Flo boot will call /system/bin/conn_init which does a whole lot of verifying your mac address and then writes out a config with the mac address in it. Very annoying. To get around this you need a copy of the wifi configs and manually enable the wifi driver since it does not start on boot. The firmware.service is only needed since I do not load the firmware in the initramfs (which I am haven't done yet)

1: Copy /system/vendor/firmware [android] to /usr/lib/firmware [arch] 2: rm /usr/lib/firmware/wlan/prima/{WCNSS_qcom_cfg.ini,WCNSS_qcom_wlan_nv.bin} <-- these are simlinks 3: cp /data/misc/wifi/{WCNSS_qcom_cfg.ini,WCNSS_qcom_wlan_nv.bin} /usr/lib/firmware/wlan/prima/ <-- these are the files which conn_init writes your mac address to

4: Copy firmware.service to /etc/systemd/system/ 5: ln -s /etc/systemd/system/firmware.service /etc/systemd/system/multi-user.target.wants/firmware.service

6: cp wpa_supplicant-nl80211@wlan0.service /etc/systemd/system/ and then ln -s /etc/systemd/system/wpa_supplicant-nl80211@wlan0.service /etc/systemd/system/multi-user.target.wants/wpa_supplicant-nl80211@wlan0.service Idealy you can use the original service file but since the ramdisk does not load the module, it requires the firmware.service 7: ln -s /etc/systemd/system/dhcpcd.service /etc/systemd/system/multi-user.target.wants/dhcpcd.service 8: ln -s /etc/systemd/system/sshd.service /etc/systemd/system/multi-user.target.wants/sshd.service

Note: Disable the wpa_supplicant hook in /etc/dhcpcd.conf

To get fbterm console

Copy fbterm/getty@.service to /etc/systemd/system/ and fbterm/fbterm-login to /opt/fbterm-login and then systemctl enable getty@tty1.service

ln -s getty@.service autovt@.service to get it on all vt's

To get X working

Install xf86-video-freedreno-git (aur) Use the xorg.conf included

Instead of filling the AUR with crap you can use the mesa and libdrm PKGBUILDs included. Always use the git versions as they have the latest freedreno fixes

Your .xinitrc should contain something like ~/refresher & exec awesome

Refreshing (refresher.c)

Since the MSMFB_SW_REFRESHER does not seem to be working i wrote this instead. Just compile and put in you ~/ or whereever so xinit can run it.

Kernel stuff

You can use the kernel from here https://github.com/crondog/kernel_msm

To get Touchscreen working

Apply 0001-make-ektf3k-driver-report-non-MT-events-too.patch

Debugging

USB serial works. I had some problems connecting with the Android Composite Gadget however just using USB_G_SERIAL seems to work. To enable run systemctl enable serial-getty@ttyGS0.service and then you will be able to connect to the device via minicom or similar on /dev/ttyACM0. Getting kernel console boot messages is still a no go as the device is registered too late to work

Kernel configs

I used the following additional configs to get this working. Some might not be necessary but it helps with debugging

CONFIG_FB_MSM_DEFAULT_DEPTH_BGRA8888 (with RGBA patch from robclark) CONFIG_FHANDLE=y CONFIG_DEVTMPFS=y CONFIG_UTS_NS=y CONFIG_IPC_NS=y CONFIG_USER_NS=y CONFIG_PID_NS=y CONFIG_NET_NS=y CONFIG_DEVPTS_MULTIPLE_INSTANCES=y CONFIG_FANOTIFY=y CONFIG_FANOTIFY_ACCESS_PERMISSIONS=y CONFIG_DETECT_HUNG_TASK=y CONFIG_DEBUG_SPINLOCK=y CONFIG_DEBUG_MUTEXES=y CONFIG_DEBUG_ATOMIC_SLEEP=y CONFIG_STACKTRACE=y CONFIG_DEBUG_BUGVERBOSE=y CONFIG_SECURITY_SELINUX_BOOTPARAM=y

Build initramfs

1: Edit makebootimage.sh with paths 2: cd systemd-initramfs; find . | cpio -o -H newc | gzip > ../minimal.initramfs 3: ./makebootimage.sh

Whats Working

Wifi fb0 Audio -- Need to setup Pulse Audio as systemwide. Not sure why it does not work as a normal user You will also need the alsaucm files from libasound2-data_1.0.27.2-1ubuntu6_all.deb Bluetooth - We now have bluez5 support :) Only tested with a Wedge keyboard

Not tested

NFC