Prusa MMU3 Firmware 3.0.4: 20% Faster Filament Changes, 9 Hours Back Per Print

Nine seconds per filament swap. On a 400-change multicolor print, that compounds to one hour saved. On a detailed model with 3,777 filament changes, Prusa’s MMU3 firmware 3.0.4 returns nearly 9.5 hours — with the same hardware you already own.

What Changed in the Firmware

Prusa’s firmware update targets three specific bottlenecks in the filament swap cycle. Each eliminates dead time that was previously baked into conservative sequencing:

Parallel Idler Disengage — Previously, the extruder waited for the MMU to disengage the idler before pushing filament. The updated firmware overlaps these operations: the extruder begins pushing while the MMU disengages in the background. Approximately two seconds recovered per swap.

Predictive Idler Staging — The MMU now pre-stages the idler during the unload retraction phase rather than waiting for retraction to complete. Another second eliminated.

Smoother Unload Ramp-Up — A refined pressure-relief step during retraction prevents extruder stalls, enabling faster retraction speed overall.

The cumulative result: swap time drops from approximately 52 seconds to approximately 42 seconds — a 20% improvement that applies to every filament change in a print. Compatible printers: MK4S, MK3.9, MK3.5, CORE One, CORE One+. Required versions: printer FW 6.5.3 or newer and MMU3 FW 3.0.4.

When the Savings Become Significant

The 9-second gain is invisible on a single swap. The math changes with scale. Prusa’s benchmarks:

• 400-change print: approximately 1 hour saved
• 2,200-change model: 5.5 hours saved
• “Lighthouse” model at 3,777 changes: 33,993 seconds saved — roughly 9.4 hours

For print farms or anyone running MMU3 production volumes, this is a meaningful operational improvement without any capital outlay. The update also adds a “Preload All” quality-of-life feature: preload all filaments of the same type at once rather than clicking through each slot individually.

Prusa’s competitive benchmarks on CORE One with a 0.4mm standard nozzle show approximately 40–50% faster PLA output and 73% less wasted filament versus comparable competitor multi-material systems. FW 3.0.4 extends that margin further.

The CORE One L Decision

Alongside the firmware announcement, Prusa addressed a frequently asked question: there will be no official MMU3 kit for the larger CORE One L. The reason is the forthcoming INDX system — Prusa’s next-generation multi-material architecture supporting up to eight toolheads — which shifted development resources away from a dedicated CORE One L configuration.

CORE One L users who want multi-material capability today can adapt the CORE One+ MMU3 kit using free conversion parts on Printables.com. The caveat is the larger buffer plates: these cannot be easily printed at home. Prusa provides STEP and DXF files for users to source them through local fabrication.

The INDX announcement is the longer-term signal: Prusa’s multi-material roadmap is moving toward toolhead-based systems, with the MMU3 continuing as the current-generation option for as long as community demand supports it.

Source: Prusa Research Blog

Content created with AI assistance and reviewed for accuracy.