This guide is intended for developers with basic ESP32 experience. ZECTRIX Note 4C is a 4.2-inch black, white, red, and yellow four-color e-paper development board. Its firmware is not compatible with the monochrome Note 4.
The firmware below is only for the ZECTRIX Note 4C four-color display. Do not flash it onto the monochrome Note 4 or an ESP32-S3 development board with different pin definitions.
Download the Note 4C merged firmware (mergebin.bin)
notellm-2bp-v6.5.9-2bp-3fbbabb-20260705-mergebin.bin0x000026f209f7cdea8f62bff73f2e877e3ab421917c17497a2a23340129c6ef43fc360x0000.Do not disconnect the USB data cable, close the webpage, or allow the computer to enter sleep mode while flashing is in progress.
Install esptool:
python3 -m pip install --upgrade esptool
Open the firmware download directory, replace the serial port with the port detected on your computer, and run:
python3 -m esptool \
--chip esp32s3 \
--port /dev/cu.usbmodemXXXX \
--baud 460800 \
write-flash 0x0 notellm-2bp-v6.5.9-2bp-3fbbabb-20260705-mergebin.bin
On Windows, replace python3 with python and use the actual COM port. If the connection fails, hold BOOT, briefly press RESET, release BOOT, and run the flashing command again.
LazyYoun/youn-ink-fourcolor-firmware
The current default branch is 2bp. Before building the firmware or starting secondary development, read the repository's latest README, commit history, and Issues.
zectrix-s3-epaper-4.2Main pins:
| Function | GPIO |
|---|---|
| Up button | 39 |
| Down button / power-related function | 18 |
| BOOT / confirm button | 0 |
| E-paper DC | 10 |
| E-paper CS | 11 |
| E-paper CLK | 12 |
| E-paper MOSI | 13 |
| E-paper RESET | 9 |
| E-paper BUSY | 8 |
| E-paper power | 6 |
Do not flash this firmware onto an ESP32-S3 development board with different pin definitions.
Four-color e-paper refreshes slowly. After pressing a button, wait for the current refresh to finish and avoid rapid repeated input.
When the device starts for the first time without any saved Wi-Fi network, the firmware automatically enters setup mode. If it does not:
ZecTrix. This hotspot has no password by default.http://192.168.4.1Use a 2.4GHz Wi-Fi network. The ESP32-S3 cannot connect to a network that only provides 5GHz Wi-Fi.
Display issue after the first connection: After the device connects to Wi-Fi successfully for the first time, the Gallery page may still show “Not Connected.” This is a known status-refresh issue and does not necessarily mean that the device is offline. Press RESET once to reset the device manually, or switch to another page and then return to Gallery to refresh and display the actual connection status.
Network: InkScreen-AP
Password: 12345678
http://192.168.4.1 in a browser.The webpage automatically scales the image and converts it to four colors in the browser. You do not need to convert the image to BIN format in advance.
Make sure you distinguish between the two hotspots:
ZecTrix...: Used for initial home Wi-Fi setup; no password.InkScreen-AP: Used to upload images to Gallery; password: 12345678.After the device connects to your home Wi-Fi:
http://device-ip/ (replace device-ip with the IP address shown on the device).The local-network page lets you upload images, preview the four-color conversion, display and manage images, and configure a slideshow. The device IP address may change, so always use the address currently shown on the Settings page.
The currently available merged firmware for Note 4C is:
Download notellm-2bp-v6.5.9-2bp-3fbbabb-20260705-mergebin.bin
0x000026f209f7cdea8f62bff73f2e877e3ab421917c17497a2a23340129c6ef43fc36Before flashing, verify the filename, file size, and SHA-256 checksum.
0x0000.Do not disconnect the USB data cable, close the webpage, or allow the computer to enter sleep mode while flashing is in progress.
python3 -m pip install --upgrade esptool
Common serial-port formats on macOS:
/dev/cu.usbmodemXXXX
/dev/cu.usbserial-XXXX
On Windows, serial ports are commonly named COM3, COM4, and so on.
Run the following command from the directory containing the firmware file:
python3 -m esptool \
--chip esp32s3 \
--port /dev/cu.usbmodemXXXX \
--baud 460800 \
write-flash 0x0 notellm-2bp-v6.5.9-2bp-3fbbabb-20260705-mergebin.bin
On Windows, replace python3 with python and replace the serial port with the actual COM port.
If the tool cannot connect automatically:
The merged firmware must be written to 0x0. Do not use a standalone OTA application image as if it were merged firmware.
Firmware project:
LazyYoun/youn-ink-fourcolor-firmware
git clone https://github.com/LazyYoun/youn-ink-fourcolor-firmware.git
cd youn-ink-fourcolor-firmware/firmware
The repository README currently recommends ESP-IDF 6.0. After entering the ESP-IDF environment, run:
idf.py set-target esp32s3
idf.py menuconfig
In the configuration menu, confirm:
Xiaozhi Assistant
└── ZecTrix EPD panel type
└── 4-color BWRY SSD2683 EPD
Corresponding configuration:
CONFIG_ZECTRIX_EPD_PANEL_4COLOR_SSD2683=y
Then build and flash:
idf.py build
idf.py -p /dev/cu.usbmodemXXXX flash monitor
Replace the serial-port name with the device port detected by your computer. To exit the monitor, press Ctrl + ].
The source code and four-color display driver in the current public repository can be used for reading and development, but a clean build may still be affected by the completeness of the publicly available files:
2bp, and there is currently no Git tag that directly corresponds to the available version.Before beginning development, read the repository's latest README, commit history, and Issues, and use the repository's current state as the source of truth.
Software development support is not included by default. You can give the GitHub link to an agent such as Codex or Workbuddy and ask it to explain the code and assist with development. If you are unsure whether the device has a hardware issue, contact:
Tao will help coordinate answers during working hours.