Category: <span>Drivers</span>

Close-up of a Raspberry Pi Pico board: micro-USB connector, BOOTSEL button and power components

“USB Serial Device (COMx)” with no vendor driver: which chips and boards Windows 11 binds to usbser.sys, and why others get Code 28

Windows 10 and 11 bind their own usbser.sys to any USB device that reports class 02h/02h, so Pico, Leonardo, SAMD, TinyUSB, STM32 CDC and ESP32-S3 boards need no download. CH340, CP2102, FT232R and PL2303 are vendor-specific and land in Other devices with Code 28. The class codes from each board's firmware source, and how to check yours.