Firmware Update: Sunlu T3

Do not use the SD card you print from—it is likely fragmented or has bad sectors. Use a fresh 8GB or 16GB SD card formatted to FAT32 with a 4096-byte allocation unit size.

Do not use random Google Drive links. Official sources:

🔍 The Sunlu T3 is a rebranded version of the Kingroon KP3S in some hardware revisions. Some users successfully use KP3S firmware, but proceed with caution.

Avoid random Google Drive links from forums unless trusted. Malware disguised as firmware.bin is rare, but a corrupted file will brick your printer.

The Sunlu T3 firmware update is not a mystical ritual reserved for engineers. With a properly formatted SD card, the correct files, and a little patience, you can bring new life to your printer.

Whether you are fixing a bug, adding safety features, or preparing to compile Marlin 2.1.x, the process outlined above will keep your T3 humming smoothly. Remember: Always back up your original settings, never interrupt the power during a flash, and when in doubt, consult the Sunlu community forums.

Your perfect print is waiting for you—just update the brain first.

Have a specific issue with your Sunlu T3 update? Leave a comment below or visit the official Sunlu Discord for real-time help.

Here’s a concise review of the Sunlu T3 firmware update process based on common user experiences and technical notes. Sunlu T3 Firmware Update

Update only if you have a specific problem (thermal runaway, ABL not saving). Otherwise, keep the stock firmware. If you want better features, skip official updates and go straight to Marlin custom builds (e.g., from Insanity Automation or TH3D) – they’re more reliable and add advanced options like linear advance.

Rating: 2.5/5 – It works, but Sunlu’s poor documentation and two-step (mainboard + screen) process make it frustrating for beginners.

It was a typical Monday morning for John, a tech enthusiast who spent most of his free time tinkering with gadgets and devices. As he sipped his coffee, he received a notification on his phone about a new firmware update for his Sunlu T3 3D printer. The update promised to improve the printer's performance, fix some bugs, and add new features.

John's curiosity was piqued, and he quickly logged into his Sunlu account to learn more about the update. After reading through the changelog, he decided it was worth updating. He downloaded the firmware file and prepared his T3 for the update.

As he began the update process, John's mind wandered back to the day he first unboxed his Sunlu T3. He had been impressed by its sturdy build and user-friendly interface. Over time, he had grown to appreciate the printer's reliability and accuracy. However, like any device, it wasn't perfect, and John had encountered some issues with print quality and filament compatibility.

The update process was straightforward, and John followed the on-screen instructions carefully. The printer's screen flickered as it rebooted, and the progress bar moved steadily. Twenty minutes later, the update was complete, and the T3 restarted.

John was eager to test the updated firmware. He loaded a new print job, a intricate vase design he had been meaning to try out for weeks. As the printer sprang to life, John noticed an immediate difference. The print head moved with increased precision, and the extruder seemed to be applying the filament more smoothly.

The print quality was noticeably improved, with fewer stringing issues and a more even finish. John was impressed by the update's impact on the printer's performance. He spent the next few hours experimenting with different print settings and materials, pushing the T3 to its limits. Do not use the SD card you print

As the day went on, John discovered that the update had also addressed some of the issues he had been experiencing with filament compatibility. The T3 was now able to handle a wider range of filaments, including some specialty materials he had been wanting to try.

The update had also brought some new features, such as improved support for calibration and a more intuitive interface for adjusting print settings. John appreciated the attention to detail from the Sunlu team, who had clearly listened to user feedback and made a concerted effort to address common pain points.

As the sun began to set, John reflected on the update's impact on his printing experience. The Sunlu T3 had always been a reliable workhorse, but the firmware update had elevated it to a new level. He was excited to see what other improvements the future held for his trusty 3D printer and the Sunlu team.

From that day on, John continued to push the boundaries of what was possible with his Sunlu T3, exploring new materials, techniques, and projects. The update had breathed new life into his printing endeavors, and he was grateful for the opportunity to take his creations to the next level.

Thermal Runaway Protection is non-negotiable. While the T3 shipped with it enabled, later firmware versions have refined the algorithms to reduce false positives while still shutting down the printer if the thermistor fails. This prevents potential fire hazards.

Updating the Sunlu T3’s firmware is straightforward if you follow the steps above. While the printer works well out of the box, a modern firmware can iron out small annoyances and occasionally add useful features like M600 filament change or better mesh bed leveling.

If you’re not experiencing any issues, you don’t need to update. But if you’re chasing better print quality or fixing a specific bug, go for it – just proceed patiently.

Have a successful update story or a problem not listed? Let us know in the comments. 🔍 The Sunlu T3 is a rebranded version

This report outlines the procedures, benefits, and risks associated with updating the firmware on the

(Terminator) 3D printer. The Sunlu T3 is equipped with a 32-bit motherboard, typically a modified version of the BigTreeTech SKR Mini E3 V2 Update Overview

Updating firmware on the Sunlu T3 can improve performance, fix factory bugs, and unlock features like increased hotend temperatures or optimized bed leveling. Official Version v3.40 (released Oct 2022) Firmware Type Marlin 2.0 Primary Method microSD Card (Auto-update on boot) Key Hardware STM32F103 MCU (32-bit) Preparation & Requirements Before beginning, ensure you have the following: MicroSD Card: Must be formatted to with a small allocation size (e.g., 4096 bytes). Firmware File: file named exactly firmware.bin for official/custom Marlin, or specifically configured for Official Downloads: Available via the Sunlu Support Page (v3.40 is the latest stable official release). Update Procedure (SD Card Method) Obtain the correct file for your specific machine version. Ensure the microSD card is clean and formatted to FAT32. Copy the file to the root of the SD card and rename it to firmware.bin Turn off the printer. Insert the SD card into the printer's slot.

Turn on the printer. The screen may remain blank for 10–30 seconds while the update installs.

Once the UI loads, check the "About Printer" or "Info" menu to confirm the new version number. Critical Considerations & Known Issues klipper/config/printer-sunlu-t3-2022.cfg at master - GitHub

Since Sunlu does not use a standard "download center" for end-users and the T3 is a rebadged version of a popular printer, here is the complete guide to finding and installing the firmware for the Sunlu T3.

Turn off the printer and remove the bottom panel (usually 4 screws). Look for the version printed on the circuit board: