S1 Upgrade Kit Install Guide

Overview

The S1 Upgrade Kit is designed to improve the reliability of the original S1 by replacing the gearboxes and the filament junction with the newest versions, now printed in ASA for greater durability and resistance to wear. These upgrades make the original S1 more robust in daily operation, reducing reload issues and extending its usable life.

Importantly, the filament junction and motors included in the Upgrade Kit are the exact same components used in the S1 Plus, giving you the benefit of the latest proven hardware.

What You Get with the Upgrade Kit

• New Gearboxes & Filament Junction – Stronger, smoother, and more reliable filament handling.
• ASA Components – Critical printed parts are now made from ASA, offering improved durability and heat resistance compared to PLA.
  S1 Plus Hardware – The filament junction and gearboxes are identical to those used in the S1 Plus.
• Reliability Boost – Better long-term performance without having to replace your entire S1.
  
  

What the Upgrade Kit Does Not Add

Because the main PCB of the original S1 is not replaced, the Upgrade Kit does not include:

• Wi-Fi Connectivity
• App Integration (no S1 Plus App connection)
• Adjustable Preload Force (remains fixed, unlike the app-controlled setting in the S1 Plus)
• Electrical Safety Features found in the S1 Plus mainboard, including:
• Motor backdrive protection
• Variable motor current via firmware for cooler, quieter operation
• Overvoltage protection (safeguards against improper power supplies)

How It Compares

• Original S1 – PLA-based parts, fixed preload, no app or Wi-Fi, fewer safety protections.
• S1 Upgrade Kit – Original S1 electronics, but with new ASA gearboxes, S1 Plus filament junction, and S1 Plus motors for improved reliability.
• S1 Plus – Full redesign: ASA components, Wi-Fi + app connectivity, adjustable preload, and added safety/electrical protections for maximum durability.

If you already own an original S1 and want to extend its life with stronger parts, the S1 Upgrade Kit is the right choice. But if you’re looking for full app connectivity, adjustable preload force, and advanced electrical safety, the S1 Plus is the correct solution.

Upgrade Kit Installation

Removing the Old Components

1. Disconnect Lower Bowden Tubes from the S1 Plus and set them aside.

2. Remove the filament junction cover by lightly squeezing the cover and pulling it off of the S1.

3. Remove the three philips philips screws holding the cover on.

4. Carefully lift the case off—it should come off easily. Unplug the main power switch in the case to get it out of the way.

5. Disconnect the Filament Junction Wire from the PCB and unscrew the two philips head screws holding on the filament junction and remove it.

6. Disconnect the gearbox runout switches from the PCB.

7. Unscrew the gearboxes from the S1 and remove them.

Installing the Upgraded Parts

1. Reverse the S1 Motor Gears. Use blue thread locker when reinstalling the set screw.

2. Line up the motor and the gearbox on the S1 Frame.

3. Install the three long M3 screws holding on the Gearbox.

4. Plug in the filament runout switch.

5. Line up the filament junction so that the two inlets are facing towards the motors on the S1.

6. Install the two philips head screws that hold on the filament junction and plug in the Filament Junction Wire.

Installing the Necessary Firmware

1. Enter firmware update mode:

• • Press and hold the boot button (shown in image below).
  • While holding the button, plug a USB->USB-C cable into your computer and the S1.
  • If done correctly, the S1’s lights will turn white instead of red.

2. Access the device storage:

• • Open File Manager on your computer.
  • A new drive named "RPI-***” will appear—this is the S1’s firmware storage.

3. Download the S1 Upgrade firmware here. Unzip the file if necessary.

• • This firmware will not work on the S1 without the upgrade kit.

4. Update the firmware:

• • Locate the .uf2 file in your File Manager.
  • Drag and drop the downloaded firmware file into the "RPI-***" drive.
  • The S1’s lights will turn bright white once the update is complete. It is now ready to calibrate.

Calibrating the Upgraded S1

Only upgraded S1's can be calibrated. Attempting to calibrate an S1 without the upgrade kit will not work.

1. With the S1 still plugged into the USB for power, install the filament junction cover. This is needed to set the limits of the filament junction levers,

2. Push the side B filament junction lever all the way down until the light on side B turns green. See the image below for reference.

3. Push all the way down on the Side A filament junction lever until the light on side A turns green then release it and DO NOT TOUCH EITHER LEVER. Wait for the lights to turn white and then green on each side. 

4. The calibration sequence should finish and both lights will turn red. The S1 is now ready to use.
5. If the calibration sequence fails or you make a mistake, follow the steps below to erase the data and recalibrate the upgraded S1.

How to Recalibrate the Upgraded S1

Only upgraded S1's can be calibrated. Attempting to calibrate an S1 without the upgrade kit will not work.

1. Enter firmware update mode:

• • Press and hold the boot button (shown in image below).
  • While holding the button, plug a USB->USB-C cable into your computer and the S1.
  • If done correctly, the S1’s lights will turn a dim white instead of red.

2. Download the flash_nuke.uf2 file here which will be used to erase the previous calibration. Unzip the file if necessary.
3. Erase the Calibration:

• • Locate the flash_nuke.uf2 file in your File Manager.
  • Drag and drop the downloaded firmware file into the "RPI-***" drive.
  • The "RPI-***" drive will disconnect and reconnect to your computer once its storage is reset. 
  • Do Not unplug the board until it reconnects to your computer automatically.

4. Follow the instructions above to reinstall the necessary firmware. 

• • If the calibration data was successfully cleared, the lights should turn bright white after uploading the IF_S1_UPGRADE.uf2 file. 
  • If the lights turn red, the calibration data was not cleared. Follow steps 1-3 of this section again to clear the calibration data.

Finishing Up

1. Carefully place the cover back on, ensuring that wires fit into designated slots (shown in image below). Make sure to plug in the main power switch.

2. Secure the three screws back into place to hold on the cover.

2. Snap the filament junction cover back into place

4. Reinstall the Lower tubes of the S1