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Allowing Access to the Phone's Hardware

A project log for Hacking an Iris 3000 Videophone

This project has to do with my attempt of gaining full access to an ACN Iris 3000 videophone.

The SycoraxThe Sycorax 01/10/2021 at 20:310 Comments

[Continued from previous log entry]

Having Debian running on the phone was good and all but to do anything useful with it I had to first set it up so that I could install software packages and give it access to the phone's hardware. The first step was to give Debian access to the phone's hardware devices. This can be done by using the "mknod" command, which is mainly used to create the character and block devices that populate /dev/. Tutorials on how to use mknod can easily be found on the internet. 

Just for reference here is a link to the Linux Device List >>> https://tinyurl.com/yysktwsq.This list is the official registry of all allocated device numbers and /dev/ directory nodes for the Linux operating. When using the mknod command this device list is a very important reference to have when populating /dev/ with character or block devices.                                                                       

                                         Accessing the Display

I wanted to first give Debian access to the Linux Framebuffer device (/dev/fb0) which is what drives the phone's LCD display. To do that I issued the following command:

mknod /dev/fb0 c 29 0

I then used the "ls /dev" just to make sure that fb0 was added to /dev/. Which it was (Pictured below).

The next step was to test the framebuffer device in order to see if Debian can actually make use of it and display some form of graphics. I did this by issuing the following command:

cat /dev/urandom > /dev/fb0

 The command will basically write random pixels to the phone's display as pictured below.

To clear the display I used the command:

cat /dev/zero > /dev/fb0

                                                                  

                                          Accessing User Input

Now that Debian was able to access the framebuffer and display graphics to the screen, I then wanted to get user input working by giving it access to the phone's keypad (/dev/input/event0). So I first created the input directory at /dev/ with the command "mkdir /dev/input/". I then issued the following command to add "event0" to /dev/input/.     

mknod /dev/input/event0 c 13 64

As I did previously did with /dev/fb0, I checked to make sure that event0 had been successfully added to /dev/input/ (Pictured below). 

I then tested to make sure that input on the keypad was working properly. I did this by issuing the following command:

cat /dev/input/event0 | hexdump

This command will basically output a hexdump of the the data received from the phone's keypad as I press down on it's keys. 

*To return back to the shell use Ctrl+C.

                                                What's Next?

Now that Debian has access to these two main hardware devices, the next thing that I wanted to do is to download and install software on the phone.

[To be continued in next log entry...]

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