You can through the browser program of PocketDuino, writing.

1.Please connect to the same LAN as the PC you turn on Wifi of Android, launch the browser.
2.If you put a PocketDuino, pop-up, such as a USB device field selection will come up, please answer it.
3.URL is displayed on the screen when you start this app, please go to the URL in the browser of your PC.
4.The browser of the PC, upload button and file selection menu and Upload hex file. Since come out, please upload and select the hex file to be written.
5.If Dere and Upload Successful screen of Android, we can upload.

including how to create .hex file, please visit the official site PocketDuino details.
http://www.physicaloid.com/product/pocketduino/