Olinuxino Disable USB device

I've found that the onboard wifi on my Olinuxino adapter wasn't working very well so I decided to shut it off and use an external adapter.

To do this you can use the following steps:

1. List the usb devices

root@debian:~# lsusb 
Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 002: ID 05e3:0608 Genesys Logic, Inc. USB-2.0 4-Port HUB
Bus 002 Device 005: ID 0cf3:9271 Atheros Communications, Inc. AR9271 802.11n
Bus 002 Device 004: ID 0bda:8176 Realtek Semiconductor Corp. RTL8188CUS 802.11n WLAN Adapter

2. Find your device

root@debian:~# cat /sys/bus/usb/devices/2-1.4/idProduct 
8176

3. Turn off the network interface

root@debian:~# ifconfig wlan6 down

4. Disable the usb wifi adapter

root@debian:~# echo 1> /sys/bus/usb/devices/2-1.4/remove

5. Check if it disappears

root@debian:~# lsusb 
Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 002: ID 05e3:0608 Genesys Logic, Inc. USB-2.0 4-Port HUB
Bus 002 Device 005: ID 0cf3:9271 Atheros Communications, Inc. AR9271 802.11n

6. Check kernel messages:

root@debian:~# dmesg | tail -n 2
[ 4229.480000] usb 2-1.4: reset high speed USB device number 4 using sw-ehci
[ 4229.600000] usb 2-1.4: USB disconnect, device number 4

*** UPDATE ***

Fast way to find and remove the device:

root@debian:~# find /sys/ | grep wlan6 | grep dev_id | cut -d'/' -f -8
/sys/devices/platform/sw-ehci.1/usb2/2-1/2-1.4
root@debian:~# echo "1" > /sys/devices/platform/sw-ehci.1/usb2/2-1/2-1.4/remove

Olinuxino A13 Memory Benchmark

Small test of Internal NAND memory and external micro SD Card for Olinuxino A13:

• External microSD Memory:
• Brand:     G.SKILL
• Size:      16GB
• Model:     FF-TSDG16GA-C10
• Website: http://www.gskill.com/products.php?index=499
• System:

• root@debian:~# uname -a
  Linux debian 3.0.42+ #1 PREEMPT Fri Nov 9 02:04:58 EST 2012 armv7l GNU/Linux
  

• Results:

• root@debian:~# dd if=/dev/mmcblk0 of=/dev/null bs=2M count=100
  100+0 records in
  100+0 records out
  209715200 bytes (210 MB) copied, 10.2158 s, 20.5 MB/s
  root@debian:~# dd if=/dev/nandi of=/dev/null bs=2M count=100
  100+0 records in
  100+0 records out
  209715200 bytes (210 MB) copied, 41.9207 s, 5.0 MB/s