Updating Firmware & PrusaSlicer Profiles

Checking your current firmware version

Settings → HW Info → Firmware on the LCD shows the currently installed version. Compare it against the latest stable release on Prusa's website before deciding whether to update.

Updating firmware

1. Download the latest .hex firmware file for the MK3S+ specifically (not the MK3 or MK2.5 — using the wrong model's firmware can cause incorrect thermal or motion behavior).
2. Copy it to the root of the SD card — not inside a folder.
3. Insert the card and power-cycle the printer; it will detect and flash the new firmware automatically.
4. After flashing, re-run Calibration → XYZ Calibration — a major firmware update occasionally resets calibration data.

Tip: Read the changelog before updating. Occasionally a new firmware version changes default settings (like pressure advance or input shaping availability) that are worth knowing about beforehand.

Keeping PrusaSlicer current

PrusaSlicer bundles print profiles for Prusa's own filaments and periodically updates them with better-tuned defaults. When PrusaSlicer prompts you about a configuration update, it's almost always safe to accept — it won't overwrite your own custom profiles, only offer newer stock ones alongside them.

Custom filament profiles

If you've tuned your own settings for a specific filament (temperature, retraction, cooling), save it as a new profile rather than editing Prusa's stock ones directly — stock profiles get overwritten on the next configuration update, and you'd lose your tuning.