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[Sticky] 3.3.0 Firmware for Original Prusa CW1/CW1S  

Same Old Shane
Member Admin
3.3.0 Firmware for Original Prusa CW1/CW1S


Greetings all, we are happy to announce the release of the latest firmware for our CW1 / CW1S. Please see the update below along with the link to download. 


  • Extend all timers to a maximum of 255 minutes of runtime
  • IPA Filtering (new feature)
  • Wash cycles (new feature)
  • New heating algorithm
  • Automatic fans control
  • Factory reset option
  • Improved self-test
  • Code refactoring and optimizations
  • Bugfixes

This is the final release of firmware 3.3.0, which is a direct successor to the previous stable release 3.1.0. Please note that firmware 3.2.0 was not released publicly and was used only for internal testing purposes. Attention, the firmware is not universal, each device requires its own firmware file!

Extend all timers to a maximum of 255 minutes of runtime

The maximum adjustable time for all operations has been increased to 255 minutes. This is especially useful for technical resins which may require longer washing or curing times for printed parts. The new firmware eliminates the need for manually repeating shorter cycles, as users can now set a longer cycle instead.

IPA filtering (new feature)

A new feature has been added to aid in filtering IPA (isopropyl alcohol) by removing resin pigment and filler from previously used IPA. (LCD menu -> IPA Filtering). The process involves solid particles being caught on the IPA pigment filter's surface and has a fixed cleaning time and turbine rotation speed. To ensure the effectiveness of the filtration process, it is important to rotate the turbine in one direction only. Alternating the direction could result in previously trapped particles being released from the filter surface back to the IPA. As a result, it is not recommended to use the regular wash cycle, which, with the new firmware, may involve alternating directions. More information on this topic can be found below.

Wash cycles (new feature)

After conducting extensive testing, we have verified that alternating the direction of rotation of the magnetic turbine is more effective for cleaning most types of prints. This firmware now enables users to set the number of cycles (1-10), which represent changes in the direction of rotation (LCD menu -> Settings -> Rotation settings -> Wash cycles). A single cycle involves turning the turbine in one direction for a specific duration of time, and the default value is 1 cycle, which means there will be no change in direction during the entire wash. By adjusting the number of cycles, users also modify their length accordingly.

New heating algorithm

The original heating method has been revised for both CW1 and CW1S, with the goal of maintaining the temperature set in the chamber. Reflecting that the thermistor has been relocated in the CW1S compared to the CW1, we have differentiated the behavior of the firmware for the two devices.

The common result for both devices is that the target set temperature is equal to the maximum temperature reached within the chamber. These adjustments were necessary, especially for longer heating times when CW1 significantly overheated the chamber with the old method. If you have had your favorite heating temperatures, you may need to revise these settings while using this firmware.

Automatic fans control

Prior to this version, the fans were set to a fixed speed. The fans are now controlled according to the cooling demand. In most cases, they can remain at the lowest possible speed and increase to the maximum only when the temperature rises. This may affect device noise during certain operations.

Factory reset option

A factory reset option is now available in the advanced settings. This new feature provides users with the ability to restore their device's settings to their original defaults. If you encounter any issues with your device or have made changes to the settings that you wish to undo, this option is a convenient solution that can help you restore your device to its original state.

You can do the Factory reset by following these steps:

  1. Select “Settings” in LCD Menu
  2. Long-press the Control knob for 2 seconds - the advanced settings menu will show up
  3. Select “Factory reset”
  4. Confirm by selecting “Really reset all?”

Improved self-test

The UV LED and heater test run only for the necessary time instead of a fixed time. Please note that there are some HW limitations and thus not all scenarios can be caught in the self-test. Such as:

  • a disconnected UV LED
  • disconnected stepper motor of the rotating platform

Code refactoring and optimizations

  • The code for CW1 and CW1S was split into separate files for easier modifications.
  • The Makefile was improved to support the build of different devices via the command line option.
  • Plugable USB in the USBCore library was disabled to save space. It was not used.
  • The menu with live values of fans' RPM and temperatures was removed to save space. It was used only for debugging purposes and had no importance for the user.
    Note that building with Travis is no longer supported and future releases will not be released using this system due to the limiting of terms of use on the Travis side.


  • This firmware does not handle info pages as menus - The information page is displayed as scrolling text only and allows you to view the entire serial number.

Download link:

Please report any bug here:

Shane (AKA FromPrusa)

Posted : 16/05/2023 2:47 pm
Eminent Member
RE: 3.3.0 Firmware for Original Prusa CW1/CW1S

How do I install this new firmware?

Posted : 23/11/2023 7:37 pm