The Twin Duck firmware is nothing short of amazing. It makes the USB Rubber Ducky show up as both a HID Keyboard and Mass Storage - just like a regular USB drive. There are a few limitations, but nothing that hinders this payload. Specifically the Twin Duck is only capable of executing payloads of 2048 keystrokes (4K inject.bin files). It also only supports a transfer speed of about 150 KB/s - which is about 9 megabytes per minute. That said it is a fantastic firmware perfect for this situation.