"ST9501C" / "CBU" RGB LED String Controller: Flashing OpenBK , steps & preca

I've just opened up my garden (IP44 rated) RGB(W?) Light Bulb string controller.
This has a BK7231N powered CBU board, labeled ST9501C.
This is clearly driving a WB2812/SK6812 style LED string as there is a +, - and Din (Data) line going out to the LEDs.

This board resets itself into a flashing state waiting for a tuya-app to connect it to the cloud, everytime I want to use it. And I don't like that.
So, I want to flash it with the OpenBK firmware. I've already got a few devices working with it for over two years now.

I just want to check before continuing whether there is something I should do for the community to extract something before flashing the new firmware.
Next steps for me is to trace the Tx / Rx / Reset and Power pins and solder on a serial connection

btw: I couldn't flash it with CloudCutter before. I've tried that a year ago, but failed, so now I've opened the device

You should always do 2MB flash backup. You can share it if you didn't pair with Tuya. Then you can flash OBK and setup PixelAnim driver as in the tutorial: https://www.elektroda.com/rtvforum/topic4057187.html

So, I finally got around to flash openbk on this.
The windows flash tool just worked fine!
My string now 'works' using your pixelanim example
startDriver SM16703P
SM16703P_Init 16
startDriver PixelAnim
But there it also fails:
This appears to be a chip which supports more than just RGB



This is the last light on the string, that's why no OUT connections, but it is clearly just one data line, as there is also just one leaving the controller.
Any chance the _init could be accepting a white (or warm cold?) channel?
Right now, while set to 16, the 15 bulbs are not all lit, let alone the colors ;)



(Everything was set expected to show the same color)



Added after 54 [minutes]:

Now I've set init to 20, that makes up for 60 colors.
(R G B × 20 = R G B W × 15)
When I set white, then all individual lights are turned on.
So I'd only need one extra channel for white.

>>21372198
Any chance there could be a White channel added to the firmware for the PixelAnim driver?