Friday, September 28, 2018

How to remove Dell Latitude E6420 BIOS password

During laptop booting, press F2 enter BIOS setup interface. Click the "Unlock" button and write down the serial number on the screen (it is case sensitive number), type the string to http://www.bios-pw.com/ and "Get password". Use the one generated by serial number and type it in on the laptop, NOTICE AFTER TYPE IN, PRESS "CTRL+ENTER" and this super password will clear current password. The idea is most of modern hardware has a builtin backdoor to allow a pre-define super password to overwritten existing one, Err... Sounds very interesting :D. Hopefully this is for users' convenience. By any means it is way better than Apple's total lock-down philosophy.

Learn something new everyday!

Monday, August 13, 2018

Super cheap Xbox 360 wireless adapter built on Raspberry Pi Zero and ENC28J60 ethernet module

I have two Xbox 360 consoles and today I want to connect them together but I only got one wireless adapter looks like this
and it is super hard to reach the back of the console after you stuck it to the TV cabinet XD.

OK, let's look this at EBGames and Ebay, WHAT! AU$48 for a second hand one! I bought my second Xbox 360 for AU$75 only. There must be a cheaper way.

Internet tells me that the easiest alternative is to use a wireless router as wireless repeater to provide ethernet connection to Xbox. But the cheapest wireless router support repeater mode is about AU$50 already and don't even think about the additional power supply and bulky router box. I remember that I used to share my wireless connection to ethernet from my Mac Mini to Xbox, so if I can do the same with a super cheap computer, then I can build my own wireless adapter.

Talking about super cheap computer, who can beat our old friend Raspberry Pi Zero! Order one from Core-electronics directly for AU$10.48 incl. shipping. Now I need an Ethernet module and PC USB wireless dongle. According to Raspi.TV, ENC28J60 chip is supported by Raspbian out of the box, so search the key word in Ebay and find the cheapest one. I bought my one for about AU$4.00. According to my reading, EDUP wireless adapter is well supported by Raspberry Pi and it is super cheap as AU$2.99 on Ebay. Adding other pieces the total cost is:

Raspberry Pi Zero: $10.48

ENC28J60 Ethernet Module: $4.00

EDUP wireless adapter: $2.99

USB OTG cable: $1.00
USB charging cable: $1.00
0.5M Cat5 Ethernet cable: $1.00
Male to Female jump leads: $1.00
2GB Micro SD card: $4.00
Total: $25.47

Hooray! Just half of the official second hand adapter price!


Now let's do it!

Step 1: Download the Raspbian image from https://www.raspberrypi.org/downloads/raspbian/, since we only need the wireless bridge feature, just download the smallest RASPBIAN STRETCH LITE image (The image size is 1.8GB and after burning, there is still 700MB free space on my 2GB SD card). Then burn it to the Micro SD card. I am using the official Mac guide https://www.raspberrypi.org/documentation/installation/installing-images/mac.md and you can find all the guides from https://www.raspberrypi.org/documentation/installation/installing-images/README.md.

Step 2: Change the keyboard layout to US, otherwise, you won't be able to type double quotation from your US layout keyboard.

Log in to the console via default username and password:
raspberrypi login: pi
Password: raspberry
pi@raspberrypi:~$ sudo vi /etc/default/keyboard
Change the line

XKBLAYOUT="gb"

To

XKBLAYOUT="us"

Save the file and reboot your Pi.

Step 3: Connect the Edup wireless dongle to Raspberry Pi Zero and enable it. I use the static IP address just for easy debug and safety.

pi@raspberrypi:~$ sudo vi /etc/network/interfaces
allow-hotplug wlan0
auto wlan0
iface wlan0 inet static wpa-ssid "<My SSID>" wpa-psk "<My Password>" address 192.168.1.254 netmask 255.255.255.0 network 192.168.1.0 broadcast 192.168.1.255 gateway 192.168.1.1

wpa-ssid is your wireless name, wpa-psk is your wireless password, other settings are set according to your wireless router requirements.

Save and reboot your Pi, your wireless adapter should work by now.

Step 4: Prepare the SPI configuration for ENC28J60 module

pi@raspberrypi:~$ sudo vi /boot/config.txt
Uncomment the line by removing the start # symbol

dtparam=spi=on

Add following line

dtoverlay=enc28j60

Shutdown your Pi and let's getting to the hardware part.

Step 5: Connect the cables between Pi and ENC28J60. According to Raspi.TV (the photo on their website actually misconnect the 3.3v lead :D), we only need connect 7 leads:

ENC28J60      Pi
INT/LNT       Pin 22 (BCM 25)
SO            Pin 21 (BCM 9/MISO)
SCK           Pin 23 (BCM 11/SCLK)
Q3/3.3        Pin 17 (3.3v)
GND           Pin 20 (GND)
CS            Pin 24 (BCM 8/CE0)
ST            Pin 19 (BCM 10/MOSI)


Step 6: Set up the bridge between the wireless adapter and ENC28J60 ethernet module according to pathead's instruction. I add the installing dnsmasq package and auto open iptables steps.

pi@raspberrypi:~$ sudo apt-get install dnsmasq
pi@raspberrypi:~$ sudo vi /etc/network/interfaces
allow-hotplug eth0 iface eth0 inet static address 172.24.1.1 netmask 255.255.255.0 network 172.24.1.0 broadcast 172.24.1.255
pi@raspberrypi:~$ sudo mv /etc/dnsmasq.conf /etc/dnsmasq.conf.orig
pi@raspberrypi:~$ sudo vi /etc/dnsmasq.conf
interface=eth0 # Use interface eth0 listen-address=172.24.1.1 # Explicitly specify the address to listen on bind-interfaces # Bind to the interface to make sure we aren't sending things elsewhere server=8.8.8.8 # Forward DNS requests to Google DNS domain-needed # Don't forward short names bogus-priv # Never forward addresses in the non-routed address spaces. dhcp-range=172.24.1.50,172.24.1.150,12h # Assign IP addresses between 172.24.1.50 and 172.24.1.150 with a 12 hour lease time
pi@raspberrypi:~$ sudo vi /etc/sysctl.conf
Uncomment the following line

net.ipv4.ip_forward=1

pi@raspberrypi:~$ sudo iptables -t nat -A POSTROUTING -o wlan0 -j MASQUERADE
pi@raspberrypi:~$ sudo sh -c "iptables-save > /etc/iptables.ipv4.nat"
pi@raspberrypi:~$ sudo vi /lib/dhcpd/dhcpd-hooks/70-ipv4-nat
iptables-restore < /etc/iptables.ipv4.nat

pi@raspberrypi:~$ sudo vi /etc/rc.local
Add following line before "exit 0"
iptables -t nat -A POSTROUTING -o wlan0 -j MASQUERADE

exit 0

Shutdown your Pi and ready to use it!

Before I plug in my home-made adapter, there is no Available Networks

Plug in the ethernet and USB cable

Pi Zero starts working...

Yes! We have an available Wired Network

Run the network connection test, looks good

Check the IP address which is allocated by our Pi Zero dnsmsq

Since we are only using 3.3v and the whole thing can run by normal USB port! Of course if the power is not sufficient, I have a plan B because I have replaced my broken factory power supply by a normal computer ATX 350W power supply with additional external chassis cooling fan :D

My ATX-box power supply

And external chassis cooling fan

Enjoy hacking!

SIZEOFINFINITY[∞]


References:
Ethernet On Pi Zero - How To Put An Ethernet Port On Your Pi - Raspi.TV
https://raspi.tv/2015/ethernet-on-pi-zero-how-to-put-an-ethernet-port-on-your-pi

How To: Wifi to Ethernet Bridge(Updated for RPi 3) - Raspberry Pi Forums
https://www.raspberrypi.org/forums/viewtopic.php?t=132674