Example: Alcor AU6476 supports firmware upgrade via custom vendor request ( bmRequestType=0x40 , bRequest=0xA0 ). Reverse engineering the Windows update tool ( AlcorFwUpdate.exe ) reveals the protocol. For AU9214, the default baud rate is often 9600 8N1. Use a logic analyzer on TX/RX pins or socat on Linux:
# Linux: unbind generic driver, bind usb-storage echo -n "1-2:1.0" > /sys/bus/usb/drivers/usb/unbind echo -n "1-2:1.0" > /sys/bus/usb/drivers/usb-storage/bind Many Alcor readers store firmware in SPI flash or internal ROM. Using dfu-util (if DFU class implemented) or fwupd (Linux Vendor Firmware Service) may detect it. alcor micro usbdev
When plugged in, these enumerate as a with multiple interfaces — each memory slot appears as a separate logical unit (LUN). Without proper drivers, Windows sees the top-level device as “Alcor Micro USB Dev.” Example: Alcor AU6476 supports firmware upgrade via custom