Ssue with Nebular 350 (Larger PCB variant): Flashes and registers, but screen does not update

Hardware
1

Hi everyone,

I’m running into an issue flashing one specific hardware variant of the Hanshow Nebular 350 with Open Epaper Link.

I have two different types of the Nebular 350:

  1. Smaller PCB variant:

    image
    image429×480 38.4 KB

  2. Larger PCB variant:

    image
    image954×660 67 KB

The Working Setup (Smaller PCB)

I was able to successfully flash the smaller PCB variant using the following setup:

Pinout (UART Flasher ----> Epaper):

  • GND ----> GND
  • VCC (3.3V) ----> VCC
  • DTR ----> NRST
  • RX ----> SWS

Tools used:

After flashing, the smaller PCB’s display changes immediately, and I am able to push content to it without any issues.

The Issue (Larger PCB)

The larger PCB variant is not working correctly, despite using the exact same hardware setup. I have tried selecting all available 350 models in the flashing tool.

  • What works: The firmware flashes successfully, and the E-paper connects and is registered by my Spaghetti AP.
  • What fails: The screen does not change after flashing and remains unwritable.

Does anyone have any hints on how to get the larger PCB variant working? Are there specific firmware versions, different pinouts, or display driver quirks I should be aware of for this specific board?

Thanks a lot in advance!