The Sunlu T3 (also known as the Terminator 3) is a high-speed FDM printer marketed for its ability to reach speeds of up to 250mm/s. While its hardware—a dual-gear extruder and 32-bit silent mainboard—supports this, the firmware is the true engine behind these capabilities.
Whether you are looking to restore the official factory settings or push the machine's limits with custom builds, this guide covers everything you need to know about Sunlu T3 firmware. 1. Official Sunlu T3 Firmware
The stock firmware is a specialized version of Marlin 2.0. Its standout feature is the "Fast Print" mode, an algorithm that optimizes acceleration and speed values directly from the printer's interface to cut printing times by up to 50%. Core Features:
16-Point Auto Bed Leveling (ABL): Uses an inductive sensor to compensate for bed irregularities.
Clog Detection: Automatically pauses prints if the filament stops moving, a rare feature in this price bracket.
Silent Stepper Support: Configured for TMC2209 drivers to maintain quiet operation (approx. 45 dB).
Where to Download: The official firmware.bin files are hosted on the Sunlu Support Page and archived by community members on GitHub. 2. Custom Firmware Options: Marlin vs. Klipper sunlu 3d - Facebook
Updating the firmware on your SUNLU T3 is the best way to unlock its full potential, especially for high-speed printing (up to 250mm/s) and fixing common fan mapping issues. Why Update Your T3?
Correct Fan Mapping: Stock firmware often has the extruder cooling fan mismapped, meaning it only runs when motors are active. Updated configurations ensure it runs whenever the hotend is hot, preventing heat creep.
Enhanced Performance: Newer versions of Marlin (like 2.0 bugfix) provide better stability for the T3's modified BTT SKR Mini E3 V2 board.
Safety & Features: Firmware updates can address security vulnerabilities and improve compatibility with modern slicer software. How to Get "Proper" Firmware
Instead of relying on outdated factory files, many users opt for community-verified Marlin configurations.
Download Official Marlin: You can find the base firmware and release notes on the Marlin Firmware Download page.
Use Verified Configurations: Anson Liu has contributed a dedicated configuration to the Marlin GitHub repository that specifically fixes the T3’s cooling fan pins and optimizes the TMC2209 stepper drivers. Compile & Flash:
Edit your configuration in VSCode using the Auto Build Marlin plugin. Place the resulting .bin file onto a formatted SD card.
Insert the card into the printer while powered off, then turn it on to flash. Hardware Compatibility Note
The SUNLU T3 uses a custom mainboard. If you are upgrading to a different probe (like a CR Touch or BLTouch), ensure your firmware configuration matches the specific sensor pins on your board to avoid leveling errors.
Sunlu T3 (Terminator 3) runs on a variant of Marlin 2.0 firmware. It is built on a 32-bit architecture, using a modified version of the BTT SKR Mini E3 V2 Go to product viewer dialog for this item. board with TMC2209 stepper drivers. Key Firmware Features
Fast Print Mode: A signature feature that claims print speeds of up to 250mm/s.
Auto Bed Leveling (ABL): Supports 16-point or 25-point (5x5) leveling via a factory-installed 3D Touch sensor.
Clog Detection: Built-in intelligence to detect nozzle blockages.
Filament Runout Detection: Automatically pauses prints if filament breaks or runs out.
Power Loss Recovery: Resumes printing after a sudden power failure.
Z-Offset Tuning: Allows real-time babystepping to adjust the first layer height while printing. Official vs. Custom Options SUNLU T3 3D Printer review----from the-gadgeteer sunlu t3 firmware
0;1052;0;2cb; 0;908;0;f1; 0;88;0;98; 0;279;0;17a; 0;1247;0;b19;
18;write_to_target_document1a;_kmjtad3fDYfFkPIPrsqPsQc_10;56; 18;write_to_target_document7;default0;1e1;
18;write_to_target_document1a;_kmjtad3fDYfFkPIPrsqPsQc_20;56; 0;ed5;0;709; 18;write_to_target_document7;default0;1e1;
18;write_to_target_document1a;_kmjtad3fDYfFkPIPrsqPsQc_20;178;0;5ce; (also known as the "Terminator 3") runs on Marlin-based firmware and is often described as an Ender 3 clone using a modified version of the BTT SKR Mini E3 V2 board0;e27; Go to product viewer dialog for this item.
0;bb7;0;8fa; with TMC2209 stepper drivers in standalone mode. While the printer is praised for its "Fast Print" mode capable of speeds up to 250mm/s, users frequently seek firmware updates to fix bugs like cooling fan misassignments or to add features like Linear Advance. 0;16;
18;write_to_target_document7;default0;bfc;18;write_to_target_document1a;_kmjtad3fDYfFkPIPrsqPsQc_20;92;0;a3; 0;baf;0;6d3; Firmware Options 0;16;
There are three main paths for updating or replacing the firmware on your T3: 0;16; 0;47b;0;45f;
Official SUNLU Firmware: Historically difficult to find on their official website, some users have found updates hidden in the SUNLU Download Center0;500; under "More" buttons.
Custom Marlin Builds: Community members have created optimized versions based on Marlin 2.1.x. These often include:
Improved ABL0;414;: 5x5 point grid instead of the stock version.
Advanced Features: Linear Advance, S-curve acceleration, and PID tuning for both the bed and hotend.
Bug Fixes0;455;: Correcting the extruder cooling fan, which in stock versions may only turn on when motors move rather than when the hotend is hot.
Where to find: Check repositories like denizkoekden's GitHub0;603;0;9f3; or Kaot93's Printables page0;a71;.
Klipper: For those wanting maximum performance and a web-based interface, Klipper configurations are available. You will need a secondary device like a Raspberry Pi to run it. 18;write_to_target_document7;default0;bfc;18;write_to_target_document1a;_kmjtad3fDYfFkPIPrsqPsQc_20;2a; How to Install New Firmware 0;16;
The SUNLU T3 typically updates via its microSD card slot: 0;16; 0;265;0;522;
Prepare the SD Card: Use a small-capacity microSD card (e.g., 8GB or 16GB) and format it to FAT32 with a 4096 allocation unit size.
Add the File0;ee;0;4d7;: Rename your firmware file to firmware.bin and place it in the root directory of the card.
Flash the Board: Turn off the printer, insert the card, and turn it back on. The screen may stay blank for 10–30 seconds while it flashes.
Confirm0;8f3;: Once the printer boots to the main menu, navigate to the configuration menu to "Save Settings" or "Load Defaults" to ensure the new EEPROM values are active. 0;2a;
18;write_to_target_document7;default0;33c;18;write_to_target_document1a;_kmjtad3fDYfFkPIPrsqPsQc_20;a5; Known Firmware Issues & Fixes 0;16;
18;write_to_target_document1b;_kmjtad3fDYfFkPIPrsqPsQc_100;57; 0;996;0;61d;
18;write_to_target_document7;default0;33c;18;write_to_target_document1b;_kmjtad3fDYfFkPIPrsqPsQc_100;26c;0;7f3;
18;write_to_target_document7;default0;5b9;18;write_to_target_document1b;_kmjtad3fDYfFkPIPrsqPsQc_100;fa4;0;2354; SUNLU T3 Marlin Configuration and Controller Board Pictures The Sunlu T3 (also known as the Terminator
(Terminator 3) firmware is generally reviewed as functional for standard printing but flawed for its advertised high-speed features
. While the hardware is considered robust for an Ender 3 clone, the stock firmware often requires community-made patches or alternative configurations to reach its full potential. Official Stock Firmware Review Strengths: Includes essential features out of the box like Auto Bed Leveling (ABL) clog detection
, and filament run-out sensors. It is simple for beginners to use at standard speeds of 60-70mm/s. The "Fast Mode" Flaw:
The most significant criticism involves the advertised 250mm/s "Fast Mode". Reviewers noted a "pause" bug during layer changes in the stock code, which creates pressure-induced blobs that often lead to failed prints at high speeds. Configuration Bugs:
Users found that the original firmware mismanaged the cooling fans; the extruder fan only activated when motors were moving, rather than when the hotend was hot, potentially causing heat creep. It also lacked PID temperature support for the bed. Community & Custom Firmware Alternatives
Because the Sunlu T3 is open-source and uses a 32-bit board (a clone of the BTT SKR Mini E3 V2), many users recommend switching to custom firmware. Custom Marlin Builds: Builders like
have released Marlin 2.1.2-based firmware that fixes the USB functionality issues of some early builds and improves ABL to a 5x5 grid. These versions often enable PID tuning and higher nozzle temperatures.
For those wanting to actually hit 250mm/s with high quality, is the preferred choice. It utilizes Input Shaping
to eliminate the ghosting and artifacts that occur at high speeds, which the stock Marlin firmware cannot handle effectively. Official Updates:
Sunlu has released updates (e.g., version 2.6.0.0) which reportedly improved remote camera connections but left many underlying high-speed bugs unaddressed. Sunlu T3 / Terminator 3 3d printer review
Optimising Your : The Ultimate Firmware Guide is a powerful machine, marketed for its impressive 250mm/s print speed
. However, to truly unlock its potential or fix persistent bugs, you’ll eventually need to dive into its firmware. Since the T3 is largely an Ender 3 clone , it relies on Marlin-based software to function.
Updating your firmware isn't just about "having the latest version"—it’s about performance, safety, and compatibility
. Here is everything you need to know about managing the brain of your Why Update Your T3 Firmware?
While you don't need to update every week, there are several key reasons to consider a flash: New Features: Access advanced
features like Linear Advance or Input Shaping to improve print quality. Bug Fixes:
Resolve issues with thermal runaway protection or leveling inconsistencies. Hardware Upgrades:
If you add a BLTouch sensor or a new motherboard, a firmware update is mandatory to tell the printer how to use the new parts. Where to Find Firmware
Because SUNLU’s official support pages can sometimes be difficult to navigate, the community has stepped up: Official & Archived Marlin: You can find the Official SUNLU T3 Firmware archive on GitHub , which allows you to fork and modify the code yourself. Marlin vs. Klipper: Most users stick with
because it is reliable and easy to learn. However, power users looking for even higher speeds may look into
, though this requires an external controller like a Raspberry Pi. How to Flash Your SUNLU T3 Format your SD Card:
Use a high-quality SD card (8GB or smaller is often best) and format it to 4096 allocation unit size Download the
Get the appropriate firmware file for your specific motherboard version. Rename the file: Requirements
Some boards won't flash if the filename is the same as the previous one. Try naming it something unique like firmware_0415.bin
Insert the card into the powered-off printer, turn it on, and wait about 15–30 seconds. The screen may stay blank during this process—this is normal. Pro Tip: Thermal Runaway Always ensure your new firmware has Thermal Runaway Protection
enabled. This is a critical safety feature that shuts the printer down if it detects the heater is out of control, preventing potential fires.
Are you looking to install a specific upgrade like a BLTouch on your T3? denizkoekden/SUNLU-T3 - Marlin 3D Printer Firmware - GitHub
update.bin or private.binfirmware.bin) to an empty SD card..bin file to avoid re-flashing.Fix: Invert the endstop logic. Open your firmware Configuration.h and look for X_MIN_ENDSTOP_INVERTING. Set it to false if it is true (or vice versa). You may need to recompile.
Flashing the TH3D or stock firmware onto a Sunlu T3 is straightforward, but specific.
This is the step most users forget. The Sunlu T3 has a separate microcontroller on the LCD screen (usually a DWIN or DACAI screen). If you update the mainboard firmware but not the screen firmware, you may see:
To update LCD firmware:
DWIN_SET folder (containing .bmp and .bin files) to the card.| Version | Date | Changes | |---------|------------|---------| | V1.0.0 | 2022-03 | Initial release (buggy ABL) | | V1.1.8 | 2022-09 | Improved bed leveling, added PID autotune menu | | V1.2.5 | 2023-02 | Fixed TMC UART errors, added M600 (filament change) | | V1.3.0 | 2023-12 | Thermal runaway sensitivity adjusted, English labels fixed |
While designed for Ender 3 V2, Mriscoc’s "Professional Firmware" works flawlessly on the Sunlu T3 with a 4.2.7 board.
Why install Mriscoc?
Installation for Mriscoc on T3:
firmware.bin.Warning: The LCD connector on the T3 is sometimes wired differently than the Ender 3 V2. If you flash Mriscoc and get a blank screen or "No Printer Attached," your ribbon cable might need to be reseated or you need the DWIN display firmware update.
If you can't find a pre-built file, compiling your own Marlin is the ultimate solution. It is easier than you think.
Requirements:
Configuration.h and Configuration_adv.h files.Critical settings for Sunlu T3:
// In Configuration.h #define MOTHERBOARD BOARD_CREALITY_V427 // Or V422 #define SERIAL_PORT 2 #define BAUDRATE 115200// Thermistor #define TEMP_SENSOR_0 1 // 100k NTC
// Bed size #define X_BED_SIZE 220 #define Y_BED_SIZE 220
// Stock display #define CR10_STOCKDISPLAY // For standard LCD
// BLTouch (if used) #define BLTOUCH #define AUTO_BED_LEVELING_BILINEAR
After editing, connect your PC to the T3 via USB (use Pronterface to find the COM port). Click "Build" in PlatformIO, then upload. Once verified, you can export the .bin to an SD card for future flashes.