When you turn on the power, the bootloader will automatically detect the firmware.bin file on the card and begin the update. The LCD screen will stay blank or show a firmware‑update message for a short while.
Preparation prevents a bricked mainboard. Gather these items before proceeding:
Your SD card might not be formatted correctly, or the file name is too long. Re-format to FAT32, rename the file to a short name like firm.bin , and try again. ❌ The printer ignores the file and boots normally
After a successful firmware update, a few simple tasks will ensure your printer is ready to produce high-quality prints: Sunlu T3 Firmware Update
Navigate to the printer menu: > Advanced Settings . Select Load Factory Defaults .
If something goes wrong, do not panic. Most issues are easily fixed. ❌ The screen stays black permanently
Use a high-quality card (8GB to 16GB is ideal). When you turn on the power, the bootloader
– It works, but Sunlu’s poor documentation and two-step (mainboard + screen) process make it frustrating for beginners.
Re-run the manual and automatic bed leveling sequences from scratch. Manually recalibrate your Z-offset before attempting your first print to avoid damaging the print bed. If you are looking to take your Sunlu T3 a step further, Share public link
Ready to take the leap? Gather your SD card, head over to Sunlu’s official download page, and give your printer the software upgrade it deserves. Gather these items before proceeding: Your SD card
(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.
The screen runs its own independent processor. It requires a separate update.