Raspberry Pi and SD card

The G1 uses a Raspberry Pi as the host computer that runs Klipper (the 3D printer firmware) and serves the Mainsail web interface. It is powered from inside the machine’s panel box.

What it does

• Runs Klipper — the firmware that processes G-code and controls all motion
• Hosts Mainsail — the web dashboard accessible from a browser on the same network
• Communicates with the extruder board MCU via USB
• Stores the G-code files and configuration on a microSD card

SD card

The operating system, Klipper config, and uploaded G-code files are stored on a microSD card inside the Raspberry Pi.

SD card corruption

SD card corruption can happen over time due to cumulative read/write cycles — it is not necessarily a single-event failure. Symptoms of SD corruption:

• The screen shows a partial boot sequence or error message but does not reach the G1OS / KlipperScreen interface — the screen is NOT simply black
• The machine does not become accessible via Mainsail or the display
• Plugging a USB-C smartphone charger directly into the Raspberry Pi reproduces the same boot failure (rules out a power issue from the machine side)

A corrupted SD card can be reflashed at home: download the G1OS image from the G1OS GitHub repository (→ Releases) and write it to the card with Raspberry Pi Imager (see How to reflash below, or the full G1OS installation procedure). If the card is physically failing, Ginger Additive can also ship a replacement Raspberry Pi with a pre-installed G1OS SD card.

Caution

USB drives with metal housings: inserting a USB stick with a metal housing into the G1 USB port may cause the printer to shut down immediately, due to ESD (electrostatic discharge). Klipper’s USB communication is also fragile — printing from USB is generally less reliable than uploading G-code via Mainsail. Use plastic-housed USB drives or upload files via the web interface.

When to reflash the SD card

Reflashing is rarely needed for random shutdowns or connection issues — these are almost always caused by undervoltage (see below), not software corruption.

Reflash if:

• The Raspberry Pi does not boot at all (no green LED activity) or the SD card is confirmed corrupted
• Klipper config is corrupted after a failed firmware update
• Instructed by Ginger support

How to reflash (when needed)

You can do this yourself with Raspberry Pi Imager and the G1OS image from the Ginger Additive GitHub. Short version (full walkthrough: G1OS installation):

1. Download the latest G1OS image (arm64 .img.xz for Raspberry Pi 4) from the G1OS GitHub repository (→ Releases) and extract it to a .img
2. Remove the microSD card from the Raspberry Pi (machine powered off — the slot is behind the ribbon cable)
3. Open Raspberry Pi Imager → Choose Device = Raspberry Pi 4
4. Choose OS → Use custom → pick the .img
5. Choose Storage → the SD card
6. Edit Settings: Hostname G1OS.local, Username pi, Password raspberry, enable SSH
7. Flash, reinsert into the machine, reassemble, power on
8. Connect Wi-Fi from the Klipper menu on the display, then open g1os.local in a browser (restart the router if it won’t connect)

Note

Use the G1OS image — not a generic Raspberry Pi OS image — because the G1 config is pre-installed. After a fresh install, initialize the printer with your serial number via Migration to new Configurator.

Power supply and undervoltage

The most common Raspberry Pi problem on the G1 is undervoltage — the Pi receives less voltage than required (minimum 5V) and shuts down to protect itself.

Symptoms of undervoltage

• Printer stops mid-print with no clear error on screen
• Klipper says “MCU shutdown” or “Lost connection to MCU”
• Shutdown happens during the vacuum cycle or during fast moves (high current draw)
• The display goes dark but fans stay running
• Mainsail shows the printer as disconnected

See also Klipper MCU communication lost for diagnosis steps.

Causes

Cause	Description
Shared mains circuit	Other high-power devices on the same circuit cause voltage dips
Power cut / EDF reset	The mains power momentarily drops — even 100ms is enough to crash the Pi
Loose power cable on Pi	The small cable (C3 connector) feeding the Pi inside the panel box can come loose
Weak power supply	The internal 5V rail is slightly low — can be adjusted

Fixes

1. Check the Raspberry Pi power cable inside the panel box — locate the C3 connector and make sure it is firmly seated
2. Move to a dedicated circuit — plug the G1 into a circuit with no other large loads (motors, compressors, other printers)
3. Increase the 5V output on the internal power supply — ask Ginger support for the specific potentiometer adjustment procedure
4. Install a UPS — a 3000VA / 2700W UPS prevents momentary power dips from reaching the machine

Note

UPS note: the G1 draws up to ~2000W peak. Size the UPS accordingly. The goal is runtime of a few minutes (to save the print) rather than hours.

Checking for undervoltage in Klipper logs

In Mainsail → System → Logs, look for:

• Under-voltage detected
• MCU shutdown
• Repeated restart events at the same time a shutdown occurred

If you see undervoltage events, the fix is electrical (power supply, circuit), not software.

Klipper firmware updates

Ginger releases firmware updates periodically. After an update, it is normal for:

• Klipper to restart once
• Some settings to require re-verification

If a Klipper update causes connection issues, check Mainsail → Machine → Update Manager for any pending component updates. If the issue persists, contact Ginger support.

Starting a print from the printer vs. from the slicer

• Starting from the printer display: the G-code runs locally; Ginger Slicer (on your computer) will not show progress
• Starting from Ginger Slicer: the slicer sends the file and monitors the print; errors appear in Ginger Slicer
• Both methods work — the Raspberry Pi handles the print the same way

Related notes

• Klipper MCU communication lost — MCU shutdown troubleshooting
• Power outlets (power box) — mains power setup
• Hopper suction problems — vacuum current spike can trigger undervoltage shutdown