I was excited to purchase the K2, knowing that it supported SD memory cards of up to 256 GB in size. The problem seems to be that in order to support this capability, you need to upgrade the firmware to Version 52, from Version 49, which is the current version.
However, when you install a 256 GB SD card, you'll find that the unit will power up, and it will broadcast the SSID as WiFi hotspot, but the app will not connect to the K2, or the connection will be very intermittent.
The problem seems to lie with the fact that the procedure for enabling EXFAT, and installing an SD Card which is larger than 32GB seems to be flawed, causing the device to not only have recording space available, but also to generally fail to allow the app to connect.
I've solved this problem, for now, by simply installing a 32GB SD card, and the unit is now working perfectly.