certs/

bambu_ca2.pem

Bambu Lab's shared root CA ("BBL CA2 RSA") used to verify a printer's LAN-mode MQTTS (port 8883) certificate. Current-generation Bambu printers present a certificate signed by (a chain rooted at) this CA - trust this one file instead of fetching/pinning a certificate per printer.

Source: https://github.com/bambulab/BambuStudio/blob/master/resources/cert/printer.cer
Fetched: 2026-08-28
SHA-256 fingerprint: E9:8F:19:57:8B:3F:12:4A:CE:6B:8A:24:7F:FE:DA:52:DC:99:C8:9F:D4:E7:D2:0C:82:82:99:77:B7:F3:35:02
Verified with openssl x509 -noout -text: self-signed (Issuer == Subject), Basic Constraints: CA:TRUE, Key Usage: Certificate Sign, CRL Sign - a genuine root CA, not a per-device leaf certificate. Valid until 2050.

The "CA2" name implies there was a CA1 generation before it, and at least one current model - P1P - doesn't chain to this root either: BambuStudio's resources/cert/ only has this one file (plus an unrelated *.bambulab.com leaf cert for their cloud API), so there's no second bundled file to grab for P1P. That means it's a genuine per-device certificate, the same "download it from the printer" case as the older units. CONTINUUM_BAMBU_CA_CERT_OVERRIDES (see .env.example) is a per-printer-id map for exactly this - there's no single fleet-wide override, because different printers can legitimately need different certificates at the same time.

If a printer's connection ever fails certificate verification against this file, re-fetch from the source URL above (BambuStudio ships whatever the current fleet needs) and update the fingerprint here.