The prior owner had no knowledge of the firmware upgrade, but it was calibrated a few years ago by Flir. I'm thinking Flir upgrade, but I don't know if it was intentional or accidental. Hopefully, someone has some experience with the 640 or the different firmware versions. Any idea of the difficulty of modifying the newest firmware to recognize the old WIFI and Bluetooth hardware? All other functions seems to work fine. Also, has anyone unlocked Ultramax if it wasn't original to the camera? My understanding is it's capable and Flir will unlock it for a special price, which I assume isn't just a few dollars. (Update found a link that UltraMax is a $500 upgrade (in 2018), so it might be worth having Flir doing if any hack is risky)
I'm not sure if Ultramax is realistically that useful if your not concerned about precision temperature measurements given every image must post processed in Flir Tools. I would assume that is a very time consuming if you want it done for each image.