This directory contains scripts and configuration files to automatically start Chromium in fullscreen mode on boot for a Raspberry Pi device (reTerminal DM4).

Files

start-chromium.sh - Main startup script that launches Chromium with proper configuration
chromium-kiosk.desktop - Autostart desktop entry file
README.md - This documentation file

Overview

This setup configures Chromium to:

Start automatically on boot
Open in fullscreen mode at http://127.0.0.1:8080
Avoid keyring password prompts
Prevent restore session notifications
Properly fill the entire screen (fixes Wayland/X11 fullscreen issues)
Support both fullscreen and kiosk modes (switchable via script)

Installation

Prerequisites

SSH access to the Raspberry Pi device
Auto-login enabled (required for autostart to work)
Chromium installed: sudo apt-get install chromium
wmctrl installed: sudo apt-get install wmctrl (for fullscreen forcing)

Setup Steps

Copy the startup script to the device:

scp start-chromium.sh pi@<device-ip>:/home/pi/start-chromium.sh
ssh pi@<device-ip> "chmod +x /home/pi/start-chromium.sh"

Create autostart directory and copy desktop file:

ssh pi@<device-ip> "mkdir -p ~/.config/autostart"
scp chromium-kiosk.desktop pi@<device-ip>:/home/pi/.config/autostart/chromium-kiosk.desktop

Install wmctrl (if not already installed):

ssh pi@<device-ip> "sudo apt-get update && sudo apt-get install -y wmctrl"

Reboot to test:
```
ssh pi@<device-ip> "sudo reboot"
```

Configuration

Switching Between Fullscreen and Kiosk Mode

Edit /home/pi/start-chromium.sh on the device:

Fullscreen mode (current): Uncomment the fullscreen line, comment out the kiosk line
Kiosk mode: Comment out the fullscreen line, uncomment the kiosk line

Changing the URL

Edit the --app=http://127.0.0.1:8080 parameter in start-chromium.sh to point to your desired URL.

Adjusting Delays

If Chromium doesn't start properly on boot, you may need to increase delays:

Line 25: sleep 5 - Delay before starting Chromium
Line 32: sleep 3 - Delay before forcing fullscreen

Troubleshooting

Chromium doesn't start on boot

Verify auto-login is enabled: sudo raspi-config → Boot Options → Desktop Autologin
Check if the script is executable: chmod +x ~/start-chromium.sh
Check autostart file exists: ls -la ~/.config/autostart/chromium-kiosk.desktop

Fullscreen doesn't work properly

Ensure wmctrl is installed: sudo apt-get install wmctrl
Check if X11 is being used (not Wayland): The script forces X11 with --ozone-platform=x11
Manually test: DISPLAY=:0 ~/start-chromium.sh

Keyring password prompt appears

The script includes --password-store=basic --use-mock-keychain flags
If it still appears, you may need to set an empty password for the keyring once

Restore session notification appears

The script includes --disable-session-crashed-bubble --disable-restore-session-state flags
If it still appears, clear Chromium's session data: rm -rf ~/.config/chromium/Session*

Manual Testing

Test the script without rebooting:

ssh pi@<device-ip> "pkill chromium && sleep 2 && DISPLAY=:0 ~/start-chromium.sh"

Exiting Fullscreen/Kiosk Mode

Fullscreen mode: Press F11 to toggle fullscreen, or Alt+F4 to close
Kiosk mode: Use Ctrl+Alt+T to open terminal, then pkill chromium
From SSH: ssh pi@<device-ip> "pkill chromium"

Disabling Autostart

To temporarily disable autostart:

ssh pi@<device-ip> "mv ~/.config/autostart/chromium-kiosk.desktop ~/.config/autostart/chromium-kiosk.desktop.disabled"

To re-enable:

ssh pi@<device-ip> "mv ~/.config/autostart/chromium-kiosk.desktop.disabled ~/.config/autostart/chromium-kiosk.desktop"

Chromium Flags Explained

--start-fullscreen - Start in fullscreen mode
--kiosk - Kiosk mode (no UI, harder to exit)
--noerrdialogs - Suppress error dialogs
--disable-infobars - Remove info bars
--disable-session-crashed-bubble - Disable crash notifications
--disable-restore-session-state - Don't restore previous session
--no-first-run - Skip first-run dialogs
--password-store=basic - Use unencrypted password store (no keyring)
--use-mock-keychain - Avoid keychain prompts
--ozone-platform=x11 - Force X11 instead of Wayland (better fullscreen)
--app=<url> - Run as app (no address bar, cleaner interface)

Device Information

Device: reTerminal DM4 (Raspberry Pi)
OS: Raspberry Pi OS (Debian-based)
Tested on: Linux raspberrypi 6.12.62+rpt-rpi-v8

Notes

The script waits for the desktop environment to be ready before starting Chromium
It uses wmctrl to programmatically force fullscreen after Chromium starts
X11 is forced instead of Wayland for better fullscreen compatibility
The script runs in the background and maintains the Chromium process

License

This configuration is provided as-is for use with the reTerminal DM4 project.