If you bought a Bambu Lab 3D printer in the last couple of years, you probably bought it because it just worked. No fiddling. No three hours of calibration before your first print. They made a genuinely good product, priced it reasonably, and the 3D printing community loved them for it. I have a friend who switched from his old Creality machine to a Bambu X1C around 2023 and would not stop telling everyone how smooth it was.
So what happened in the last few weeks has been kind of painful to watch. Not because the drama was unexpected — honestly, the signs were there since early 2025 — but because Bambu took what could have been a quiet internal policy decision and turned it into one of the biggest PR disasters in 3D printing history. And they did it by going after one Polish developer with a GitHub repo.
The Background: Open Source Foundations That Bambu Built On
To understand why people are so angry, you need to know a little bit about how 3D printer software works. There’s a category of software called a “slicer” — it takes your 3D model file and converts it into the actual instructions the printer follows. For years, the dominant open-source slicer was something called Slic3r. That got forked into PrusaSlicer by the people at Prusa Research. Then Bambu Lab came along and built their own slicer — Bambu Studio — as a fork of PrusaSlicer. And in 2022, a developer named SoftFever forked Bambu Studio into a popular alternative called OrcaSlicer.
So the whole thing is a family tree of open-source code. Each project built on what came before it.
Here’s the thing about open source, though: it comes with rules. When you take open-source code and build something with it, the license you’re using determines what you can and can’t do. Bambu Studio was released under something called AGPL-3.0 — a “copyleft” license that specifically says anyone can take the code, modify it, and release their own version, as long as they also share their changes as open source. That’s the deal. You build on the community’s work, and you give back to the community. Bambu agreed to that deal when they chose to build on PrusaSlicer.
OrcaSlicer was popular not just because it was free. It had features the official Bambu software lacked — scarf seams, crosshatch infill, a built-in calibration package. A lot of serious Bambu users preferred it. For a while, Bambu and OrcaSlicer coexisted fine.
January 2025: The Update That Changed Everything
In January 2025, Bambu Lab released a firmware update that blocked third-party direct access to their printers via the cloud. The main change was something called Bambu Connect — new middleware software that sat between your slicer and your printer. Users could no longer send print jobs directly to printers they owned. Everything had to go through Bambu’s servers first, through their new software.
The official explanation was security. The company reported that its cloud servers were inundated with roughly 30 million “unauthorized” requests per day, threatening system stability. That sounds like a lot. And the argument wasn’t completely made up — unoptimized third-party software hammering a cloud API really can cause problems. I get that.
But the way they did it bothered a lot of people. They changed the rules after people had already bought hardware. This effectively forced customers to agree to new Terms and Conditions surrounding the use of their printer, which they did not agree with upon purchase of the product. If Bambu had shipped the printer with these restrictions from day one, sure, fine. But you don’t buy something under one set of conditions and then have those conditions changed by a firmware update.
The 3D printing community pushed back hard. The company released Bambu Connect at the beginning of 2025 to enhance printer security and control third-party tool integration, but it soon received backlash from users on the Bambu Lab forum. Some called it “a way for Bambu to exert more control over how printers could be accessed and integrated with third-party tools.”
Paweł Jarczak Fixes the Problem — Then Gets Punished For It
This is where it gets messy. A Polish developer named Paweł Jarczak built a fork of OrcaSlicer specifically for Bambu printers. He called it OrcaSlicer-BambuLab. His fork gave users direct access to printer functions again, which Bambu Lab had removed since introducing the Bambu Connect middleware.
He published it on GitHub on April 23, 2026. It gained traction quickly. Within days, Bambu sent him a private cease-and-desist message.
Bambu Lab’s legal response alleged that Jarczak had impersonated Bambu Studio, bypassed authorization controls, violated its Terms of Use, reverse engineered proprietary software, and enabled modified forks to send arbitrary commands to printers.
Jarczak’s response, documented on his GitHub, was basically: show me exactly what I did wrong. He asked Bambu Lab to identify, precisely and concretely, the exact repository files, commits, or code paths they considered problematic, the exact legal or contractual basis they were relying on, and the exact Terms / EULA basis if their objection was primarily about service access rather than copyright. He also made clear that the repository did not contain or redistribute their proprietary networking plugin binaries.
He did not receive the precise technical and legal clarification he had asked for. Instead, after he disputed their characterization and asked for specifics, he received further broad accusations, including repeated references to “reverse engineering”.
So he took the project down. Not because he admitted wrongdoing, but because a solo developer with no legal team cannot fight a company. This is how these situations usually go. The C&D letter doesn’t need to win in court — it just needs to be expensive enough that the person on the other end gives up.
Jarczak also maintains firmware for something called the BMCU — a DIY alternative to Bambu’s AMS (their multi-color system). He said there is a growing risk that the BMCU will also be locked out of Bambu Lab’s ecosystem and is pivoting to Klipper-based printers. I mean, at that point you’ve basically pushed one of your active community contributors out the door entirely.
The Internet Reacts: $20,000 and “Sue Us”
This is where the story stops being a quiet developer dispute and becomes something much bigger.
GamersNexus published a piece on May 12, 2026 titled “Fuck You, Bambu Lab” — rehosting Jarczak’s software with his permission and offering $10,000 USD in legal support to Jarczak if Bambu sued. Louis Rossmann, the right-to-repair YouTuber, offered another $10,000 for the same purpose. Together that’s $20,000 in legal defense funds raised in days. GamersNexus basically dared Bambu to sue them. The story hit number one on Hacker News with 848 points.
The AGPL license argument came up a lot in these discussions. Bambu Studio is open source and a fork of PrusaSlicer, which itself is a fork of Slic3r. The AGPL is structured such that anyone who uses the software is permitted to do as they like with it. Jarczak’s position was that his fork was built on publicly available AGPL source code, and the license explicitly permits derivative works. Bambu’s counter was essentially: a license for code is not a pass to our cloud infrastructure. That’s not a crazy position, but then Bambu had their own problem they weren’t talking about.
Bambu’s Bigger Problem: They Were Violating the License Themselves
On May 18, 2026, the Software Freedom Conservancy — a nonprofit organization that actually enforces open-source licenses got involved. And this is where things got genuinely serious for Bambu.
After recent news of violations of the AGPLv3, SFC staff began a comprehensive AGPLv3 compliance investigation of both the userspace software and firmware on Bambu’s devices. While the investigation is ongoing, two specific AGPLv3 violations have been confirmed. First, Bambu does not provide the complete, Corresponding Source Code for their Slicer software.
The second violation: the SFC identified that Bambu had bundled a proprietary networking library without releasing the source code mandated by the license, and had made aggressive efforts to threaten and shut down Jarczak’s fork, effectively curtailing his legal rights under AGPLv3.
So the short version is: Bambu threatened a developer for using their AGPL code as AGPL permits — while Bambu themselves had been violating that same AGPL license for, apparently, four years. The networking library they ship with Bambu Studio is proprietary and closed-source. Under AGPL, you can’t do that if the rest of the software is AGPL. You have to release everything. They didn’t.
Bradley Kühn, one of the people who literally wrote the AGPL license, had a comment about Bambu’s behavior. He called them, to quote, “bad actors, straight-up.” Not a great look.
Bambu Lab eventually backed down from legal pressure against Jarczak after the SFC accusations. But the damage was done by then.
What the SFC Is Actually Building Now
The SFC didn’t just send a letter. They launched a project called “baltobu” with three components: a repository to provide the network library via reverse engineering, a second repository to continue Jarczak’s OrcaSlicer fork as a canonical version, and a third called “viscose” to develop its own fork of Bambu Studio. Jarczak is involved as a collaborator.
The SFC also launched a fundraiser targeting $250,007 for dedicated staff, which had exceeded $60,000 at time of publication. And they’re setting up a permanent monthly committee starting in June 2026 to keep an eye on open-source compliance across the entire 3D printing industry — not just Bambu.
So Bambu sent one cease-and-desist to one developer and ended up with: a $20,000 legal defense fund raised against them, GamersNexus openly daring them to sue, a formal investigation by the Software Freedom Conservancy, two confirmed license violations, a funded reverse-engineering project targeting their proprietary networking code, and the developer they tried to silence now working with the organization coming after them.
The Bigger Problem Bambu Doesn’t Want to Talk About
There’s a precedent that people keep bringing up in these discussions: MakerBot. The now-defunct manufacturer MakerBot followed a similar trajectory, shifting from open-source, DIY-focused machines to closed-source, proprietary ones, which ultimately drove customers to less-expensive open-source competitors and contributed to MakerBot losing its position as an industry leader.
Bambu’s own blog post from January 2026 didn’t exactly deny the direction they were heading. Bambu Lab officially acknowledged their choice in a blog post: “We debated whether to follow a Raspberry Pi model or adopt an approach like Apple.” It was a strategy to grow with open source and transition to closed source. So at least they’re honest about what they’re doing, I guess.
The “security” framing is the part that really bothers me. Security is a valid concern, but forcing all traffic through proprietary middleware isn’t the only solution. Better infrastructure, rate limiting, and API keys could address unauthorized requests without limiting software freedom. Those are normal engineering solutions. They’re not exotic. Any company that’s dealt with API abuse has used them. The choice to instead wall off the entire ecosystem suggests the real priority wasn’t just server stability.
And there’s a pattern here worth noting. Some consumers have noticed that more hardware features are being locked behind paid subscriptions. There are rumors that Bambu Lab is developing its own farm software, and one source claimed to have seen indications of tiered fees for different sizes of farms. You combine that with the move to force all traffic through their servers, and you start to see the shape of what they might be building toward.
Where Things Stand Right Now
As of late May 2026, Bambu has backed off Jarczak specifically — but the SFC investigation is ongoing. Baltobu is actively reverse-engineering Bambu’s proprietary networking layer. The goal, if they succeed, is that Bambu printer owners could eventually regain full local control without routing through Bambu’s servers at all.
The monthly committee on software repair law in 3D printing kicks off in June 2026. Jarczak is already confirmed as a participant.
Bambu Lab still makes good hardware. That hasn’t changed. But what they’ve done is break something harder to fix than a firmware bug — the trust of the open-source community that helped make them popular in the first place. And unlike a firmware rollback, you can’t patch your way out of that.
The weird thing is this whole mess could have gone differently. A proper public API with keys, rate limiting, and documentation would have solved the server load problem without this. Instead, they went the Apple route — closed ecosystem, everything through their servers, legal threats when someone pushed back. And they did it while building their own products on top of code they weren’t even properly complying with.
Paweł Jarczak just wanted to fix a printer he used. Now he’s working with the Software Freedom Conservancy on a project to reverse-engineer Bambu’s networking stack. I don’t think that’s what Bambu had in mind when they sent that letter.