How to Flash Anet ET4 to Marlin 2+ Firmware with ST-Link

Our user davidtgbe released his Marlin firmware files for Anet ET4, Anet ET5X series 3d printers. Today we'll have step-to-step instructions on how to flash Marlin firmware for your Anet ET4, Anet ET5X 3D printers. 

Step 1 Power On & Printer Models Confirmation

Check the printer model you have. Please be noted the Anet ET4 has two versions. One with capacitive leveling sensor. The other with NO capacitive leveling sensor on the extruder, like the picture list below. The two versions need different firmwares. 

Step 2 Get STLink Connected

Unscrew the bottom shell off. Connecting the ST-Link V2 to relative cables according to below table. 

Please be noted that the cable colors may varies from different ST-Link versions! The blow information only for the ST-Link we're taking in this tutorial.

SWDIO – Number 2 – brown wire cable

GND (Ground) – Number 4 – black wire cable

SWCLK (SW Clock) - Number 2 - orange wire cable

Connect the black wired pin to the G marked pin (the closest to the chip) on the controller board, and then connect the white wired pin to the board pin above. And at last, connect the brown wired pin to the board pin above the previous.

Note: Leave the fourth pin at the top unconnected. 

Use a USB extension cable to connect the ST-Link V2 with a PC.

Step 3 Download Compiled Marlin 2.0 Firmware

Download the compiled Marlin 2.0 firmware for Anet ET4 and ET5 series 3d printers on the following links. Get the firmware.srec file of your printer model underneath and save it on your TF card.

Step 4. Get Marlin Bootloader

Click below link and download the “openblt_et4.bin” file for ST-Link utility. 

Marlin Bootloader:

https://drive.google.com/drive/folders/1nUm2-6b9MXEj6f0sZaFXTL8Titp95k1P?usp=sharing

What is a bootloader?

A bootloader, also known as a boot program or bootstrap loader, is a special operating system software that loads into the working memory of a computer after start-up. For this purpose, immediately after a device starts, a bootloader is generally launched by a bootable medium like a hard drive, a CD/DVD or a USB stick. The boot medium receives information from the computer’s firmware (e.g. BIOS) about where the bootloader is. The whole process is also described as “booting”.

How does a bootloader work?

When you press the start button on a computer, the very first thing you see on the screen is information about the hardware installed. The software responsible for this notification is the device firmware mentioned above, which is usually implemented by manufacturers in flash memory on the computer’s motherboard. With most desktop PCs and notebooks this will be the BIOS (Basic Input / Output System) or the more modern UEFI (Unified Extensible Firmware Interface). Both applications collect the most diverse hardware data and create a complete list of all of the device’s available drives.

When this process is complete, the firmware goes through the data carriers found in sequence, checking for a bootloader by means of a special signature – the so-called boot signature (or ‘boot record’). The search always starts on the removable media (CD/DVD, USB stick, external hard drive, etc.), followed by the hard-coded drives. With the latter, the bootloader and its signature is generally in the master boot record (MBR), which also contains the data carrier’s partition tables. When a bootloader is found, it is loaded and the system start is initiated. If the search is unsuccessful, the firmware will return an error message.

Step 5 Write Marlin Firmware with ST-Link Utility

Get the “STM32 ST-Link Utility” app on the official website of ST-Link and install the app on your computer.

After installation, open the “ST-Link Utility” app. Connect the ST-Link to PC and then turn on the printer. Click the third button (plug -like) at the ST-Link utility app and it will populate the original ET4 firmware document.

Click the “Target” and then “Program” button and "Browse" button to Start to installation of the Marlin 2+ firmware by selecting the "openblt_et4.bin" file you downloaded previously.

Note: If you don’t have an ST-Link V2, you can also use a J-Link to flash an Anet ET4 3D printer to Marlin 2+ firmware.