Paxx firmware v1.6.0-paxx12-22 released

[github-actions]

A new Paxx U1 Extended Firmware release is out: v1.6.0-paxx12-22

Published	2026-09-07T19:31:04Z
Upgrade image	U1_extended_1.6.0-paxx12-22_upgrade.bin (247 MB)

The in-app download button updates itself within 24 h (client-side resolver in renderer/printers/snapmaker/paxx.js).
Optional maintenance: bump the PAXX_FALLBACK constant in that file at the next convenient release.

Release notes

Notice

Warning: While installing custom firmware does not automatically void the product warranty, any damage caused by or attributable to the installation or use of custom firmware is not covered under warranty. Use at your own risk. See Snapmaker Terms of Use for details.

If you notice a problem, always reproduce it on stock firmware before contacting Snapmaker support. Despite our best efforts, bugs can occur. Only contact support if the issue also occurs on stock firmware.

Custom firmware is intended for users with appropriate technical knowledge. Ensure you understand the implications before proceeding.

New Features and Key Changes

• Firmware updated to Snapmaker's stock 1.6.0 — see below Update firmware to 1.6.0 paxx12-snapmaker-u1/SnapmakerU1-Extended-Firmware#648 (@paxx12)
• Firmware Upgrade Channel: choose whether this project's own firmware updates are checked for (Stable/Testing/Develop) or disabled entirely, from firmware-config — no more manually blocking Snapmaker's auto-update Add firmware-upgrade imposter to allow firmware upgrades paxx12-snapmaker-u1/SnapmakerU1-Extended-Firmware#516 (@paxx12)
• DragonBreath: community open chamber-heater firmware, now the recommended option alongside Panda Breath, with a one-click LAN migration path for existing Panda Breath users — see below chamber-heater: add DragonBreath as an option alongside Panda Breath paxx12-snapmaker-u1/SnapmakerU1-Extended-Firmware#666 (@plastikman / @paxx12)
• Bypass MCU (Disconnected) mode: keep printing on the other toolheads when one toolhead's board is dead or unplugged, not just when its thermistor fails — see below Add toolhead MCU simulator for a dead board or unplugged cable paxx12-snapmaker-u1/SnapmakerU1-Extended-Firmware#678 (@paxx12)
• Add Force Generic Vendor mode to SpoolLink, for Spoolman vendors the U1/Orca doesn't recognize Add force generic vendor mode to SpoolLink paxx12-snapmaker-u1/SnapmakerU1-Extended-Firmware#619 (@Dragon2203)
• Expose the air purifier's exhaust/circulation fans as standard Klipper fan_generic objects, controllable from Fluidd/Mainsail and SET_FAN_SPEED feat: expose purifier fans as generic fans paxx12-snapmaker-u1/SnapmakerU1-Extended-Firmware#673 (@justinh-rahb)
• Fix: SET_SPOOL_ID missing a fallback for E-prefixed lanes fix(spoollink): add missing fallback for E-prefixed lanes in SET_SPOO… paxx12-snapmaker-u1/SnapmakerU1-Extended-Firmware#684 (@Fibdorius)
• Fix: filament manager's websocket connection now passes an access token, closing an authorization gap Pass access token to websocket connection in filament manager paxx12-snapmaker-u1/SnapmakerU1-Extended-Firmware#659 (@krzmaz)
• Fix: Moonraker zeroconf mDNS not resolving after boot Fix Moonraker zeroconf mDNS not resolving after boot paxx12-snapmaker-u1/SnapmakerU1-Extended-Firmware#658 (@lagnat)
• Fix: SpoolLink now resolves the correct spool on same-UID channel swaps, using CARD_EVENT_TIME Add CARD_EVENT_TIME and use it to trigger SpoolLink resolves paxx12-snapmaker-u1/SnapmakerU1-Extended-Firmware#657 (@paxx12)
• Fix: restored five PRs that were silently reverted by the 1.6.0 firmware-bump PR (#648) Restore five PRs silently reverted by #648 paxx12-snapmaker-u1/SnapmakerU1-Extended-Firmware#674 (@paxx12)
• Fluidd (v1.37.4) and Mainsail (v2.19.0) bumped to their latest versions

Full changelog: paxx12-snapmaker-u1/SnapmakerU1-Extended-Firmware#663

Firmware 1.6.0

This release bumps the base Snapmaker firmware to 1.6.0. Upstream changelog:

• Added 0.4 mm high-flow nozzle option in Print Head Information editing.
• Added selectable filament types in the Filament Details page for quicker filament matching.
• Added an AI monitoring issue report function after print completion, available only in Cloud mode, not available in Local Area Network mode.
• Improved the tip-forming effect during filament unloading, reducing the chance of failure caused by filament expansion.
• Enhanced loading and unloading efficiency, shortening waiting times.
• Fixed an issue where the device did not respond when moving the Z-axis in 0.1 mm steps.
• Fixed an abnormal page jump in the Wi-Fi Management page after tapping the Enter key on the soft keyboard.
• Fixed an issue where, after resuming a print job started via the official client, unused channels would still check filament information.
• Fixed an issue where the top-cover setup guide would not display properly after completing the U1 initial setup wizard.

See Snapmaker's official V1.6.0 release notes for the full upstream changelog.

DragonBreath Chamber Heater

@plastikman's open-source DragonBreath firmware - replacing Panda Breath firmware - is now a selectable option in firmware-config under Snapmaker Components > Chamber Heater, alongside Panda Breath, and is now the recommended option.

Nothing about an existing Panda Breath install changes automatically. If you're already on Panda Breath and want to switch, a "Migrate to DragonBreath" action flashes the DragonBreath firmware to your Panda board over Wi-Fi — no USB cable, no internet access needed on the printer or the Panda — then swaps the Klipper config over for you.

Heads up: Panda Breath support is planned for removal in a future release. If you're still on stock Panda Breath firmware, consider migrating to DragonBreath when convenient.

Control Top-Cover fans from Fluidd/Mainsail

The @justinh-rahb contributed change to control official Top Cover fans from Fluidd/Mainsail:

Bypass MCU Mode & Toolhead Simulator

Stock Klipper treats any toolhead MCU connection failure as fatal for the whole printer — one dead board or unplugged cable used to take down all four toolheads. The new "Bypass MCU (Disconnected)" mode lets you disable a toolhead whose board is dead or unplugged entirely, not just one with a bad thermistor, and keep printing on the other three.

Heroes

The Hero of this release is @plastikman, for building and maintaining DragonBreath - the open-source chamber-heater firmware that's now the recommended option for the chamber heater integration.

Install

For detailed installation instructions, see the Installation Guide.

Quick steps:

1. Download .bin and put on FAT32 formatted USB device
2. On the printer go to Settings > About > Firmware Version > Local Update
3. Select .bin and confirm.

Troubleshooting

• Persistent issues after extended recovery: Place full-recover.txt on a FAT32 USB drive and insert it while the printer is running. This performs a full wipe of printer data and overlays, then rebuilds from defaults on the next boot. Note: extensions installed over SSH (such as HelixScreen) live outside the managed overlay and may not be removed by recovery — reflash stock firmware in that case.
• Existing Spoolman spool mappings: the mapping format changed with SpoolLink — mappings are no longer stored in Lot Nr, but in a new Extra Fields > Card UID field. Existing mappings need to be moved over manually in Spoolman (strip the card_uid: prefix when moving the value).
• Tags carrying an OpenSpool spool_id: SpoolLink does not read spool_id off the tag, only card_uids. Re-scan those tags with one of the mobile apps in docs/spoolman.md to migrate them to a card_uids link.
• For the most reliable SpoolLink spool resolution, use Snapmaker's built-in RFID Detection System (firmware-config under Snapmaker Components > RFID Detection System) rather than OpenRFID/alternative detection — alternative systems aren't guaranteed to report a UID for every tag, which SpoolLink needs to resolve a spool.
• DragonBreath migration fails or the device is unreachable: confirm the Panda Breath board has a static DHCP lease and is powered on, then retry the migration from firmware-config. If it's already been flashed to DragonBreath, the migration step is safe to re-run.

Found an issue or have feedback on Spoolman/SpoolLink/the apps? Please use this issue to report it, rather than opening a new one — it helps us track feedback on this feature in one place.

Revert

1. Download .bin from the Snapmaker U1 Wiki.
2. Follow the same as for install.

Community

Join the Snapmaker Discord and visit the #u1-printer channel to connect with other users using the custom firmware, share experiences, and get help.

Support

If you find this project useful and would like to support its development, you can:

🖨️ Buy a Snapmaker U1 — ordering via the link below supports this project. Optionally use code PAXX12CUSTOM for $20 off, or any other discount you find online:

• EU store: https://snapmaker-eu.myshopify.com?ref=paxx12
• US store: https://snapmaker-us.myshopify.com?ref=paxx12
• Global store: https://test-snapmaker.myshopify.com?ref=paxx12

[BenGlut]

Offline fallback bumped to v1.6.0-paxx12-22 in renderer/printers/snapmaker/paxx.js — ships with the next release. (The in-app download button already served this version through the live resolver.)