Elegoo Releases Centauri Carbon Firmware Code, But Questions Remain
Under pressure from groups seeking transparency about the Centauri Carbon’s underlying software, Elegoo has published the “source code” for the Elegoo OS the printer uses. The release is a positive step, but appears to validate concerns that the firmware is a heavily modified version of Klipper that breaches license conditions.
A post on the Elegoo blog on September 26, 2025, announced the release, appearing to satisfy at least one demand – a peek under the hood at the underlying software that powers the machine.
Since its early 2025 launch, the Elegoo Centauri Carbon has picked up plenty of plaudits for the surprising value it offers. Concurrently, questions have been raised over the firmware it uses, and whether there were open source licensing breaches taking place.
The suspicion is that, despite Elegoo’s repeated clarifications to users and the media – including us – that the Centauri Carbon firmware is not based on Klipper, it turns out that, well, it might be. Heavily modified to work with the printer’s non-standard hardware for a Klipper implementation, but based on Klipper after all, according to the confident claims put forward in public forums and project pages dedicated to the issue. Poking around in the files posted to GitHub, it doesn’t take long to find references to Klipper and some of it’s underlying structure.
Why Does it Matter?
To briefly recap, Klipper is open source firmware shared under general public license (GPL-v3, specifically). This copyleft license requires any derivative that uses the licensed work as inspiration, framework, in modification or translation from its native programming language, is also available under the same licensing conditions. It must be made available to anyone who requests it. Typically such work is shared publicly anyway, since the purpose is often open collaboration and development. Until posting the GitHub repo, it does not appear that Elegoo had honored any requests for the printer’s source code.
Besides the obvious implication of breaching a protected work’s licensing, which would be wrong, the significance of Elegoo releasing the Centauri Carbon’s source files is that community elements can then unpick issues, and develop fixes and improvements – it is a commonly attributed benefit of open sourced work that it can be more secure than closed source developments. More eyes and attention on an issue can focus minds and share the work, versus the possibility of an issue not getting appropriate attention in a company’s priority list. At least, that’s the general idea.
A contributor to the OpenCentauri community project, which aims to discover “the secrets” of the machine and explore possible modifications, made the initial observations of connections between Elegoo’s firmware and Klipper earlier this year. Later, subsequent Reddit threads discussing the discoveries and Elegoo’s reaction, or lack of, to license requests have emerged, as has a webpage called freethecode.lol, which is dedicated to the Centauri Carbon’s apparent licensing transgression. OpenCentauri members are active in those same Reddit threads, but it is unclear who is responsible for the “Free the Code” website.
We’ve contacted Elegoo for comment, but did not receive a response before publication. In light of the claims we detail above, we’re keen to learn if Elegoo stands by its stance that the Centauri Carbon firmware is not based on Klipper, and whether it plans to add (or honor) any licencing requirements to the files it has shared.
Update – November 28,2025: Elegoo has since added license information on the GitHub files. Despite repeated questions about it, the company refuses to be drawn on previous statements saying it doesn't use Klipper.
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License: The text of "Elegoo Releases Centauri Carbon Firmware Code, But Questions Remain" by All3DP is licensed under a Creative Commons Attribution 4.0 International License.