Custom Snapmaker U1 Firmware

Anycubic ACE via multiACE

This experimental integration is provided by the rolling-only extended-multiace firmware profile. It is not included in stable firmware images. The PAXX-managed multiACE provider package is downloaded only when selected in Firmware Config; it is not bundled into the firmware image.

This integration packages multiACE, the upstream Anycubic ACE implementation created by Decay (@decay71) and developed with its contributors. PAXX provides the U1-specific packaging and firmware integration; the upstream ACE implementation is the work of the multiACE authors.

This draft pins a published multiACE release for hardware validation on the rolling extended-multiace image only. Initial printer testing confirmed that an ACE 2 Pro can reach the ready state after fixing a serial-device permission problem; filament operations and reconnect behavior are still being tested. The firmware integration remains experimental even though the provider version is a regular release.

The PAXX integration follows the same general model used by other optional third-party applications in this firmware: the provider release is pinned in the firmware source, downloaded on demand, and verified with a SHA256 checksum.

Enable it

1. Install the extended-multiace image from the project’s rolling release.
2. Open Firmware Config and then Snapmaker Components.
3. Set multiACE Integration to Enabled.
4. Confirm the action and allow the printer to reboot.

For firmware updates, select the develop upgrade channel. The rolling release includes a matching extended-multiace image; stable and testing releases do not.

Remove any separately installed or manually started multiACE copy before enabling this option. Two copies must not be active at the same time: they can both try to provide the same Klipper modules or web port.

For the adapter tested with the ACE 2 Pro (USB ID 1a86:7523), add v2_extra_usb_ids: 1a86:7523 under the existing [ace] section in /home/lava/printer_data/config/extended/ace.cfg. The default intentionally does not accept every generic serial adapter as an ACE. PAXX installs a persistent udev rule for this exact USB ID so the lava account can open the serial device after boot and USB reconnection. Verify that behavior after flashing this change; the test printer previously needed a one-time manual permission correction before the ACE reached ready state.

When enabling multiACE, PAXX checks whether the installed package differs from the firmware’s reviewed version pin and upgrades it when needed. If multiACE is already enabled, the Upgrade pinned multiACE package quick action performs the same upgrade and reboots afterward.

The first installation also installs the provider’s constrained web dependencies into the versioned MultiACE package. This may take longer than subsequent starts and requires the printer to be able to download the package and dependencies. The dependencies therefore survive reboot without requiring the firmware’s debug-persistence mode.

What PAXX manages

The firmware owns the integration boundary while the provider owns its ACE behavior:

• The exact provider release URL and SHA256 checksum are pinned in the firmware package definition.
• The release is installed under /oem/apps/multiace/ with a latest link.
• Provider Klipper modules are mounted read-only over their stock paths only when components ace: multiace is selected.
• The stock files are not overwritten. Disabling the component removes the mounts and restores the stock paths on the next Klipper start.
• Persistent configuration is kept under /home/lava/printer_data/config/extended/multiace/.
• The provider configuration is linked into the normal extended Klipper include directory only while the managed integration is enabled.
• The web UI is served through the authenticated Fluidd or Mainsail origin at /multiace/; its backend listens only on localhost.
• The managed provider package disables standalone install, uninstall, self-update, and file-copy mode switching. multiACE-to-head runtime mode changes remain available. PAXX owns package upgrades through the reviewed version and checksum pin.
• PAXX retains an idempotent cleanup for stale update-wrapper macros in persistent configs created by the older test archive; it does not pass the legacy update-disable environment flag. The managed provider package ships without those wrappers and enforces managed mode itself.

The integration uses the platform-neutral .multiace-managed marker in its persistent state directory. Decay’s managed-package PR defines this provider contract:

• MULTIACE_MANAGED=1
• MULTIACE_MANAGED_MARKER
• MULTIACE_APP_DIR
• MULTIACE_CONFIG_DIR (the directory containing printer.cfg, /home/lava/printer_data/config on the U1)
• MULTIACE_PRINTER_DATA

The marker and paths let multiACE distinguish a platform-managed install from its standalone installation without coupling provider code to PAXX-specific paths or names. PAXX passes the five-variable contract to the managed web service and preserves the provider’s default U1 paths for Klipper.

Disable or remove it

In Firmware Config, set multiACE Integration to Disabled and confirm the reboot. The PAXX service stops the web UI, removes the provider mounts, and removes the downloaded package. Persistent ACE configuration is intentionally left in place so it can be inspected or reused if the integration is enabled again.

If a package is present but cannot be activated, the activation hook fails closed: it unmounts any partial provider mounts and leaves the stock Klipper paths available. A conflicting file or an already occupied provider web port is treated as an error rather than silently replacing another installation.

Current pin and scope

PAXX pins multiACE version 1.27b from the regular v1.27b release, built from source commit a1a7b91. The exact managed archive URL and SHA256 are pinned in the package definition; the installer does not follow a moving latest release or an unverified branch. This release includes the Gen 1 tunnel and web preflight helper as required managed-package files.

There is one remaining provider-package gap: the v1.27b managed archive excludes tools/merge_ace_cfg.py, even though that helper exists in the multiACE source tree. PAXX preserves the existing ace.cfg and will invoke the provider helper during package refresh when it is present, but this release cannot merge new template options into an existing user config. Including that helper in a managed multiACE release (or an equivalent provider-supported managed migration interface) is still needed to complete safe config upgrades.

This is a draft integration for hardware testing. It has been checked for package structure, checksum verification, shell syntax, and provider-side managed-boundary tests; ACE loading, unloading, tool changes, recovery, and long-print behavior still require testing on a connected printer.

Report ACE protocol, device detection, and multiACE UI behavior in the multiACE issue tracker at https://github.com/decay71/multiACE/issues. Report firmware packaging, component selection, device permissions, and activation problems in the PAXX firmware issue tracker at https://github.com/paxx12-snapmaker-u1/SnapmakerU1-Extended-Firmware/issues.

The PR adds overlays/mods/multiace/ and a separate extended-multiace rolling image; it does not add multiACE to the stable release workflow or combine it with the AFC profile.