Group: Hardware/Computers/Printers
Introduction
The h-node website has a section about printers. But hat section is concerned about the compatibility of computers (like your laptop that runs FSF approved distributions) with existing printers.
It doesn't treat the printer as a computer that can run potentially free software.
Here this page is about research to find if it's possible to run free software on printers.
So far we only know any RYF certified 3D printers running free software, but this page is about non-3D printers.
Research
This section list and/or summarize existing security research and/or source code releases on printers.
Security research is interesting as security researcher often analyze in details the software and hardware architecture of the printers. They often tell if the printers are running GNU/Linux and on which part of the printer (for multi-function printers or big enterprise printers).
For free software source code release they may contain hints that there is GNU/Linux running (for instance if busybox is released) and/or source code for the Linux kernel.
HP MFP M725z
Vendor: HP
Product: MFP M725z
Reference: Printing-Shellz.pdf
Short summary: Runs GNU/Linux in a scanner board only.
Details
Page 8 we can see the hardware and software architecture:
+-------------------+ +-----------------+ | Scanner board | | Printer board | | running GNU/Linux |<---->[+]<---->| running an RTOS | +-------------------+ ^ +-----------------+ | +---------------------+ | | Communication board |-----+ | running Windows CE | | - 4 USB host | | - 4 USB devices | | - Ethernet 1000 | | - Touchscreen | | - Fax board | +---------------------+
It's unknown if HaRET works on that version of Windows CE.
I also didn't look at the CPU architectures or more details since GNU/Linux only runs on the scanner board.