I’m new to programming xiaos and am having simular problems, that I can get scan test working, but writing data fails. I also have another self created issue that I twisted the sda and sdl lines on my pcb. Switching pins in pins_arduino.h gets the scan test working. If this’ll make it impossible to get the data read/write working, then please could someone tell me. Any updates on which board/software versions to use would be appreciated. Thanks.