Bambu Lab Threatens OrcaSlicer Fork Developer Over AGPL Code It Wrote Itself

Jeff Geerling escalates his criticism of 3D printer maker Bambu Lab, this time over the company’s cease-and-desist threats against the developer of OrcaSlicer-bambulab, a small fork that lets users access printer features without routing print jobs through Bambu’s cloud. Bambu publicly accused the developer of an impersonation attack and posed a risk to their infrastructure, despite the fork reusing the AGPLv3 client code Bambu itself ships in its Linux build of Bambu Studio. The supposed offense — sending the official client’s user agent string — only matters if Bambu is relying on that string as a security control, which would be an architectural failure on their end rather than a vulnerability the developer introduced.

Geerling frames this as Bambu weaponizing legal threats against a single hobbyist to suppress the roughly 0.1% of customers who want to run their hardware without mandatory cloud connectivity. He notes the irony that Bambu Studio is itself a fork of Prusa Slicer (which once received Bambu telemetry by accident without legal retaliation), and that Bambu refused to let him publish the full correspondence while broadcasting a one-sided public account. Louis Rossmann has pledged $10,000 toward the developer’s legal defense.

The broader argument is that Bambu is violating the open source social contract underlying the AGPL code it depends on: take the community’s work, lock down the resulting ecosystem, then sue community members who try to use that same code outside the sanctioned cloud path. Geerling’s recommendation is simply to buy a printer from someone else.