Bambuzled
Bambu Lab’s Bind: Company Stands By Its Position in Open-Source License Fight
Bambu Lab’s critics continue to line up to take shots at the company. Following the company’s pressure to take an OrcaSlicer fork that restores the connection to its cloud service offline, attention has sharpened onto an alleged AGPL license violation that may have lived within Bambu Studio since its launch in 2022. Bambu Lab contests this.
When Bambu Lab published its “Setting the record straight” post on May 7, it addressed its dispute with developer Paweł Jarczak as one of cloud access. The company claimed Jarczak’s OrcaSlicer-bambulab was impersonating an official client, effectively gaining unauthorized access to the company’s cloud service. Cloud platforms are private infrastructure governed by terms of use, not open source license obligations, the post says.
To recap quickly, Jarczak discovered a difference in the Linux version of Bambu Studio that, combined with OrcaSlicer – itself based on Bambu Studio – restored cloud access controls: the ability to send and control the printer while logged in and using Bambu Lab’s cloud. Bambu Lab changed how third-party slicers could do this, introducing a middleware app called Bambu Connect in 2025, which the OrcaSlicer team decided not to implement. Jarczak’s slicer, working only with the available code as released by Bambu Lab, effectively rolled the clock back and restored this access.
Bambu Lab disagreed, and Jarczak – rather than facing a firm legal action – took the fork down. After talking about the interaction on social media, Jarczak’s story quickly sparked a firestorm of attention from an intersection of 3D printing, right-to-repair, and open source communities. The criticism against Bambu Lab has coalesced around a long-disputed claim of Bambu Studio breaching the open source license it is available under.
What follows has split into two parallel disputes that are legally distinct but have become politically inseparable. The first is Bambu Lab’s: that Jarczak’s fork impersonated an official client to gain unauthorized access to private cloud infrastructure, that its cloud is governed by terms of service rather than open source obligations, and that those terms extend to prohibit reverse engineering its systems – Jarczak removed his project at Bambu Lab’s request, but the Software Freedom Conservancy (SFC) has recreated it, and is now deliberately reverse engineering the networking plugin as part of its Baltobu project.
The second is the community’s: that Bambu Lab has been in breach of the AGPLv3 license governing Bambu Studio since its original 2022 fork of PrusaSlicer, specifically by treating its networking plugin as exempt when the license requires its source be made available, and also now by imposing restrictions on use of the open code (pressuring Jarczak to take his slicer down).
Bambu Lab’s intention to protect its cloud service remains a core of the company’s communication about the incident. It’s a defensible component of the dispute, but one that sidesteps what has become a larger argument against the company: accusations of breaching the Affero General Public License (AGPL) that governs its software. This has become the sticking point and lightning rod for a collection of campaigns challenging Bambu Lab’s willingness to test its legal interpretation of things, as well as now a coordinated campaign to “jailbreak” the company’s closed source networking plug-in – the component at the heart of critics’ complaints.
Jarczak, who removed his fork voluntarily after Bambu’s private C&D warning, has since published a 616-line technical document contending that Bambu Studio has an AGPL compliance problem that lives entirely within Bambu’s own software distribution, upstream of any cloud term-of-service question.
Since Bambu Studio is licensed under AGPLv3, the license it inherited when it was forked from Prusa Research’s PrusaSlicer, there’s a scope for the release of “Corresponding Source” – meaning all the code needed to reproduce the compiled software – including dynamically linked components a program is “specifically designed to require” through “intimate data communication or control flow.”
In response to questions from All3DP, Bambu Lab says it does not agree that the plugin constitutes “Corresponding Source” under AGPLv3, maintaining that it is “a separately delivered, optional networking component that provides additional functionality.” The company’s reading of Section 1 of the license holds that the covered work is not “specifically designed to require” the plugin – a distinction it says its lawyers and external experts examined when the question was first raised in 2022, and a position it reaffirms today.
In 2022, independent researcher Roy Sigurd Karlsbakk shared a post on his personal blog highlighting what he saw as an AGPL breach concerning Bambu Studio’s networking plugin. Bambu Lab saw fit to directly address Karlsbakk to assert its confidence, backed by “considerable time consulting with our lawyers” and experts, that it is not in breach. The company stands by this today.
On May 13, 2026, Josef Průša – who has never been shy about lobbing grenades in Bambu Lab’s direction – posted a thread to X restating his view that Bambu Studio has violated the PrusaSlicer AGPL since its original 2022 release – a position he says he flagged publicly in March 2023.
Prusa Research maintains the immediately upstream codebase from Bambu Studio, meaning it would hold copyright on any code that remains in the latter today, if there is any, giving it a potential compliance claim distinct from Jarczak or any end user.
Jarczak’s document, asserted by the SFC and its read on the situation, argues that Bambu Studio downloads, installs, versions, and directly pulls the bambu_networking into memory at runtime – not as distinctly separate or optional as Bambu Lab suggests. Bradley M Kühn at the SFC, who co-drafted the Affero clause that’s relevant to this situation, says it “provably” is, writing further in the announcement for its campaign against Bambu Lab on May 18 that “Bambu falsely claims that their terms of service override the AGPLv3 (along with other specious claims). Bambu’s scare tactics against Paweł constitute a violation of AGPLv3 §10¶3 – which states the matter quite simply: ‘You may not impose any further restrictions on the exercise of the rights granted or affirmed under this License.'”
Following Jarczak’s overview of what he views as Bambu Lab’s AGPL violation the Software Freedom Conservancy, in consultation with Jarczak, has publicly moved to address Bambu Lab head-on with what it calls the “Bringing Affero Licensed Things (On)to Bambu Users” (Baltobu) project, a pressure campaign of multiple components that the organization says intends to achieve short and long term change.
In a blog post on the SFC website, Kühn writes: “Bambu has behaved badly for years and made multiple, provably false public statements regarding the AGPLv3 and its requirements. The recent aggressive behavior toward Paweł Jarczak was a last straw for us.”
Talking to All3DP, Kühn elaborates, saying that he finds it “very likely there are more AGPLv3 violations ‘under the hood’. For example, We know that the Bambu Studio software connects to a network service.” Parts §1 and §13 of the AGPLv3 license interact in this situation. “If it turns out – arguendo — that Bambu has moved some of their ‘subprograms’ that interact via ‘intimate data or control flow’ with the slicer on the customer’s computer, then §13 requires Bambu to provide the Corresponding Source and Installation Information for those network services to the consumer.
I simply don’t know at this moment if that type of AGPLv3 violation is present” he admits. “Our investigation is only beginning. But, SFC plans to investigate this fully and come to a conclusion about these and other issues in the coming months.”
He continues: “SFC uses litigation as an absolute last resort. While we’ve accelerated our response with Bambu from our usual copyleft enforcement practices, our goal now is to get some useful material created that will help the consumers who have been wronged by Bambu’s AGPLv3 violations as quickly as we can. Once we do that, which will surely take at least a few months, we at SFC will reassess the situation and figure out what to do next.”
In addition to hosting the slicer that started this whole saga, Baltobu has repositories for deliberately reverse engineering the networking plugin, as well as a project it calls Viscose, a mirror of sorts to Bambu Studio that will “work toward a replacement for Bambu Studio that works better for consumers who own Bambu 3D printers” Kühn writes. The group is actively raising funds through donations to pay for a full-time maintainer to work on 3D printing campaigns including, but not limited to, Baltobu. The organization hopes to raise the target amount of ~$250,000 by July 17 – an amount that’s “less than the average cost of 300 3D printers!” Kühn says. “That amount will allow us to continue address any copyleft violations in the 3D printing industry for at least two years to come.”
Asked about the new projects designed to force its closed source code into the open, Bambu Lab told All3DP “The AGPL, the DMCA, and Bambu Lab’s terms do not permit reverse engineering that violates applicable protocols, rules, or circumvents technical protection measures protecting our cloud services… . We are aware that some people are hosting relevant codes.
From the beginning, our preference has been dialogue, not confrontation. At this stage, rather than escalating conflict, we are focusing on strengthening our own infrastructure and protection measures moving forward. Interim measures have already been implemented. Security will continue to be strengthened in future releases, and we recommend that users update to the latest version in a timely manner.”
Bambu Lab has signalled it views the reverse engineering effort as legally distinct from the open source debate. The company cites DMCA Section 1201 and WIPO Copyright Treaty Article 11 – which obliges signatory nations to provide legal remedies against circumvention of technical protection measures. “This is not a uniquely American legal concern,” the company says, “it reflects a broad international consensus on protecting secure systems.”
What changes in all this? Nothing much for now. Bambu Lab’s stance that it has handled its code appropriately remains unchanged, and it continues to view efforts to crack it as a breach of its copyright and the contract of its terms of service, while third parties are certain the company is already in breach of licensing terms and now actively works to scrutinize it closer and unpick the code.
In the statement shown to All3DP, Bambu Lab concedes its approach with Jarczak was misjudged. The company states, “we nonetheless regret that our reference to Terms of Service, legal context and a potential C&D understandably came across as a legal threat. That was not the outcome we wanted.” Jarczak says he has had no contact with the company since the initial exchange.
