Alcor Micro Usbdev Apr 2026

| Chip | USB VID:PID | Description | |------------|-------------|------------------------------------------| | AU6370 | 058f:6377 | USB 2.0 SD/MMC/MS single-slot reader | | AU6366 | 058f:6366 | Multi-LUN reader (up to 4 slots) | | AU6476 | 058f:6476 | USB 3.0 + SD 4.0 (UHS-II) |

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.” alcor micro usbdev

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: | Chip | USB VID:PID | Description |

Introduction: The Unseen Workhorse If you have ever plugged in a budget USB hub, a no-name barcode scanner, a multi-format memory card reader, or a legacy serial adapter on an industrial PC, chances are you have unknowingly used a chip from Alcor Micro Corp . While not a household name like FTDI or Silicon Labs, Alcor Micro’s USB controllers are quietly embedded in millions of peripherals worldwide. The device that often appears in system information as “Alcor Micro USB Dev” or “Alcor Micro USB Card Reader” is a fascinating case study in low-cost, high-volume USB bridge design. For AU9214, the default baud rate is often 9600 8N1

# 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.

lsusb -d 058f: -v | grep -E "idVendor|idProduct|bDeviceClass|bInterfaceClass" : Use USBDeview or Wireshark with USBPcap. Step 2 – Force class driver If the device is a card reader but appears generic: