Reverse Engineering Bambu Connect

Original Article ↗ Hacker News Discussion ↗

Context: Bambu Connect & Firmware Changes

  • New firmware introduces an “authorization control system” for critical operations (starting prints via LAN/cloud, motion/temperature/AMS control, firmware upgrades, etc.).
  • Bambu Connect (an Electron app) becomes the gateway for print jobs from slicers; direct LAN APIs and previous “network plugin” workflows are being deprecated.
  • Beta firmware and app are currently limited to some models; others are slated for later.

Security Model & Reverse Engineering Findings

  • Reverse engineering shows MQTT commands for critical actions now require signatures using a private key embedded in Bambu Connect.
  • Authentication to the printer itself (LAN access code, TLS with self-signed cert) largely remains unchanged.
  • Critics argue this adds no real security (security-through-obscurity; once the key is extracted, third-party tools can sign too).

Vendor Lock-In / DRM Concerns

  • Many see this as a shift toward DRM and cloud lock‑in, not user security.
  • Fears include potential future subscriptions, cloud dependence, and printers losing LAN functionality if Bambu stops issuing certs.
  • Others argue the change mainly adds “one extra button” and modest friction.

Impact on Workflows & Third-Party Tools

  • Print-farm software, Home Assistant integrations, and OrcaSlicer users are most affected.
  • Bambu proposes: slicers hand off to Connect via URL/protocol handler; Connect manages LAN/cloud communication.
  • Printing from SD card on the printer itself appears to remain, but there is confusion about browsing/starting SD prints over LAN.

Company Response & “Developer Mode”

  • After backlash, Bambu announced:
    • Standard LAN mode with authorization.
    • Optional “Developer Mode” preserving today’s wide-open MQTT/FTP for advanced users, but unsupported.
  • Some see this as sufficient; others see it as a fragile, non-guaranteed concession.

Open vs Closed, Alternatives, and Buying Decisions

  • Large meta‑debate: “Apple-like” turnkey experience vs open, hackable printers.
  • Bambu praised for print quality, speed, and ease-of-use; criticized for cloud dependence and retroactive restrictions.
  • Prusa, Voron, Qidi, Creality, Flashforge, etc. discussed as alternatives, each trading cost, openness, and convenience.
  • Several users say this episode pushed them away from buying (or toward freezing firmware and blocking internet).