A box of PADI IoT Stamps arrived in the mail a few weeks ago. After soldering an SoC to a carrier board, I was able to communicate with it over UART and I could bang in a few AT commands to make it do stuff.
I looked around for some Arduino integration, but it was a bit rough around the edges except for the Ameba IoT package from Realtek.
Their binary flasher only works with their mbed board/tool, and I didn't want to spend money or time waiting around for one. I came across an OpenOCD rtl8710 flasher and was able to dump the contents of a PADI IoT stamp and flash my own binaries from the command line.
This was all I needed to bodge it into a board package for Arduino.