The Ultimate Productivity Killer: Doom Arrives on the Office Desk Phone

There are few things more boring than an office phone. Those of us who have spent countless hours with these devices — enduring pointless meetings that should have been emails or fielding urgent requests that destroy the weekend — would be just fine if we never saw one again.

If an office phone suddenly appeared in your home, what would you do with it? Maybe something reminiscent of the printer scene in Office Space? That might be my first inclination, but a hardware hacker over at 0x19.co decided to go in a different direction after being given a pair of twenty-year-old Snom 360 phones from work. Since this phone has a display and buttons, you might be able to guess what it was repurposed for. That’s right: to play Doom.

The unlikely gaming platform in question is a business-class VoIP desk phone first released in 2005. Underneath its unassuming plastic shell lies a 150 MHz MIPS processor, 16 MB of RAM, and 4 MB of flash storage — hardly gaming specs, even by early-2000s standards. But as any seasoned tinkerer knows, modest hardware has never stopped Doom from finding a new home.

The project began with a firmware upgrade. After discovering that the phone’s firmware image was not encrypted and contained a JFFS2 filesystem, the hacker extracted it using binwalk and began exploring. A quick inspection revealed the device was running Linux 2.4.31 on a MIPS32 architecture.

Digging deeper uncovered statically linked binaries responsible for the phone’s interface, along with GPL-released kernel sources and a cross-compilation toolchain from the manufacturer. With these resources, custom firmware could be built and flashed back onto the phone. The real turning point came after soldering onto hidden serial test points inside the device and accessing the bootloader. From there, a custom root filesystem was deployed over TFTP, granting full shell access.

With control established, the next challenge was hardware-level reverse engineering. The phone’s 132×64 monochrome display wasn’t driven by a typical framebuffer device but instead communicated through ioctl calls to a custom kernel driver. By analyzing both disassembled binaries and kernel headers, the hacker decoded the commands required to initialize the display, write pixel data, and toggle the backlight LED.

The keypad required similar detective work. By tracing port reads and bitwise operations, individual key codes were mapped and translated into usable input events.

Rather than porting the original Doom source directly, the project leveraged a portability-focused engine requiring only a handful of platform-specific functions — display output, key input, and timing. Frames rendered at 640×400 were downscaled and converted into 1-bit grayscale to suit the LED matrix screen.

In the end, this resulted in a fully playable version of Doom running on a device originally designed for conference calls and corporate voicemail. It may not be the smoothest way to battle demons, but it’s undoubtedly one of the most satisfying transformations of office hardware in recent memory.