WSAL20828 – GPM2804/en

Documentation notice: This technical documentation was independently rewritten from an archived supplier source. Check technical details and commands against the product version and manufacturer documentation before use.

Summary

Concise technical reference for the GPM2804. It covers the display, CM4 compatibility, setting up a Retropie image via an SD card, and key configuration steps (buttons, audio, fullscreen, filesystem, ROM updates). All facts are taken only from the provided source text.

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Technical overview

The GPM2804 uses a 2.8-inch IPS display with a resolution of 640 x 480 pixels, a 70% NTSC color gamut, and a 60 fps refresh rate.
The console is compatible with the Raspberry Pi Compute Module 4 series; the CM4 is listed as optional in the product metadata.
A pre-configured Retropie v4.7 image is available; default login credentials are user “pi” and password “raspberry” (as written in the source).
To install, format an SD card with SDFormatter, write the image using Win32DiskImager, insert the card into the console, and power on via the switch.
For manual Retropie setup, place the ssh and wpa_supplicant.conf files in /boot and copy waveshare-4dpib-3b-4b.dtbo to /boot/overlays.
Append the specified DPI, GPIO, and audio parameters to config.txt, and add the line “fbcon=rotate:3 video=DSI-1:480x640M@60,rotate=90” to cmdline.txt.
Button mapping is done at the WELCOME screen by long-pressing A; unused buttons can be skipped.
The IP address is shown via CONFIGURATION -> SHOW IP; SSH access with pi/raspberry allows editing autostart.sh, retroarch.cfg, and other files.

Commands and examples – verify before use:

sudo nano /opt/retropie/configs/all/autostart.sh
emulationstation --screenrotate 3 --screensize 640 480
sudo nano /opt/retropie/configs/all/retroarch.cfg

Notes and version constraints

Password is noted as “raspberry” in the source – verify against the actual configuration before use.
The exact Retropie image version (v4.7) may be outdated; current versions should be confirmed separately.
S1/S2/S3 switches control operating modes; incorrect settings can cause unintended behavior – verify switch positions before powering on.
If battery charge is low (blinking red indicators or no indicator), the system will not start; charging requires a 5 V / 3 A adapter connected to the Micro USB port.
Changes to config.txt, cmdline.txt, and DTBO files are version-sensitive; validate them against the specific Retropie release being used.

Source and revision record

GPM2804 - Waveshare Wiki
Source revision: 110995
Captured: 2026-09-02T04:19:50+00:00
SHA-256: e15090e13c525d996f76d9b2f229bc7da68a4311aad083ce31ee4508976f610d