Month: March 2010

Degree Confluence

Thanks my friend Fernando Ataide for send me this link for a nice project. The “the Degree Confluence Project” aim to visit and take a picture of each confluence LatLong point in the earth. Each integer point will be mapped:


Prescricao de Oculos

Nao tem jeito, chega um dia que voce vai precisar usar oculos e este dia chegou:

Longe – Esférico – O.D.: -1.00 e O.E.: -0.25

Including driver firmware on Linux kernel image

Driver’s binary firmware is a dedicated issue to Linux. In fact even open source drivers usually load its firmware to internal chip and it drives some puritan GNU people to become crazy.

Unfortunately you don’t have much option because these firmware are necessary to get your device working.

When developing an embedded system you could face a “Chicken and Egg” dilemma related to firmware loading. For example, you could need to mount a root file system through NFS over wireless, but your wireless interface needs a firmware which is in the rootfs (at /lib/firmware).

Hopefully you have some approaches to solve this dilemma:
1) Create an initrd (initramfs) with needed firmware inside;
2) Include your driver built-in into the kernel.

To include the needed firmware into the kernel just select this option:

Device Drivers  --->
    Generic Driver Options  --->
    -*- Userspace firmware loading support
    [*]   Include in-kernel firmware blobs in kernel binary

Also you could specify an external firmware path at:

(/home/user/newfirmware.bin)    External firmware blobs to build into the kernel binary

How to add wireless interface on Android

I’m configuring Android to add support to wireless adapter. Unfortunately it is not easy as it is on Linux. Let walk through the process:

I started compiling Linux kernel with support to my wireless adapter RT73, basically my kernel has:


Other big mistake was the firmware path, in Linux kernel it is placed at /lib/firmware. I lost some time to figure out the right place it /etc/firmware:

$ adb push rt73.bin /etc/firmware/

After than I try to start-up wifi on Android shell this way:

# netcfg wlan0 up

Arggg, “no donuts for you” 😦

Finally I found more some nice tips here:

Again, more issues, wpa_supplicant binary doesn’t exist. After a little more researches I found the problem: I need to inform to it be build: Edit external/wpa_supplicant/ and modify:


Compile Android again.

Create a wpa_supplicant.conf (in fact just modify the ti_wlan0 one) adding your wireless interface (wlan0 in my case):


Connect in your AP:

# wpa_cli ... set_network 0 ssid "your_ap_name"
#wpa_cli ... set_network 0 key_mgmt WPA-PSK
#wpa_cli ... set_network 0 pairwise CCMP TKIP
#wpa_cli ... set_network 0 psk "makemeveryverysecret"

Configure route and DNS:

# route add default gw dev wlan0
# setprop net.dns1

An useful thread about this topic is here:


When trying to turn Wi-Fi ON using Android setting, I was getting this error message:

"unable to start Wi-Fi"

Then using “adb logcat” I can see the error:

"E/WifiService( 1935): Failed to load Wi-Fi driver"

Then I figured out the issue, Android wants loads the driver by itself, because I place the driver built-in into kernel, it will work at console, but will not work on graphic mode.

I saw some people suggesting adding it on init.rc:

setprop wlan.driver.status "ok"
setprop init.svc.wpa_supplicant "running"

Unfortunately it didn’t worked to me.

Then I changed the wifi driver to module on Linux kernel and modified “hardware/libhardware_legacy/wifi/wifi.c” to load that driver for me:

#define WIFI_DRIVER_MODULE_PATH         "/system/lib/modules/rt73usb.ko"
#define WIFI_DRIVER_MODULE_NAME         "rt73usb"

Also I copied the modules files (rt2x00lib.ko, rt2x00usb.ko, rt73usb.ko) to “/system/lib/modules” and called insmod to them in init.rc

UPDATE: Nicu Pavel created a great tutorial explaining more about Wireless on Android: