Seems likely tied to USB enumeration timing with the Adafruit BSP. Without these, there is no enumeration and thus no HID device on the host system. ``` build_flags = -DUSE_TINYUSB lib_archive = no ``` [https://community.platformio.org/t/tinyusb-on-seeedstudio-femto/18732/3](url) [https://community.platformio.org/t/tinyusb-sometimes-project-do-not-work/27518/3](url)