Hi Edwin,
Are you following the BitBank software path (and code) to install the Arduino bootloader?
I am interested. I do have an AVRISP and a couple of XBee+serial breakout boards (older XB24-AWI-001 Rev C. versions from Adafruit circa 2013, so we'll see how happy they are with each other and the IKEA Trådfri Zigbee Light Link devices). I am okay with the raw device as it comes out of the mail and happy to pick it up as well. I think that the Tigard AVRISP can connect directly to the JTAG port that is exposed in the battery compartment to install the bootloader
This might save you the soldering step that is challenging in the current weather/state of HVAC.
Let me know if I can help out.
Regards,
Pietra