đź’ˇ Tutorial: Turn Your Snapmaker U1 into a Dedicated Filament Dryer (Firmware Bypass)

Maker Creations Tips & Guides
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Snapmaker officially recommends using the heated bed and a ventilated cardboard box to dry filament. However, if you try to run a raw G4 timer script via USB to keep the bed hot, the U1’s firmware blocks it with a “Please Select Filament” error.

Here is the “Slicer Hijack” workaround to bypass the multi-toolhead gatekeeper and safely run drying cycles on the U1:

The Setup (One-Time):

  1. In SnOrca, clone your U1 printer profile and name it “U1 - Filament Dryer”.

  2. Delete everything in the Machine end G-code box so it is completely empty.

  3. Replace everything in the Machine start G-code box with this exact script:

Plaintext

M140 S65 ; Heat bed to 65C (Change for different filaments)
M190 S65 ; Wait for bed to reach target
M104 S0 ; Keep nozzle cold
M106 S0 ; Keep part fan off
G4 P21600000 ; Dwell for 6 hours in milliseconds (Change as needed)
M140 S0 ; Turn off bed heater
M84 ; Disable stepper motors
M2 ; Terminate print job immediately

How to Use It:

  1. Place your wet spool on the heated bed. (Pro-tip: Elevate the spool on four small printed cubes to protect the plastic flanges from direct conductive heat and allow airflow).

  2. Cover the spool with a cardboard box (I used the box that had contained the 4 spools) that has a few small ventilation holes poked in the top.

  3. In your new SnOrca dryer profile, add a dummy shape (like a Voron cube) to the build plate.

  4. The Trick: Assign the dummy cube to a filament profile that is currently loaded on your U1.

  5. Slice and export to your USB drive.

When you run this file on the U1, the firmware sees a valid toolhead match, allows the job to start, runs your thermal timer, and immediately terminates the print safely via the M2 command before the toolhead ever moves!

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Using U1 For Filament Drying
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Just found another method from Rodrigo Sclosa

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