Hi there!
The 2450HD (black frame, non-GPS) uses Cleanflight, while the 2450GPS (white frame, GPS) uses ArduCopter.
This last year we brought ArduCopter over to the Journey (white, GPS), Scout (Black, No GPS, but with Optical Flow) and Fury (Black, no GPS, but with Optical Flow).
For the card, you don’t need a high-speed card as it’s 720p video and not a 100Mbps 4K feed like the $1k models. Just make sure it’s formatted to FAT filesystem. And yes, the recording stops when the critical battery alarm starts. I think what’s happening here is that due to the temperature, the LiPo is having issues. I remember flying at Lake Tahoe in 20 degree (F) weather and only made it 2:30 minutes. The cold slams the battery efficiency hard, but as it’s being used, it heats up. Because of this, I think you are seeing the crit voltage being triggered, but the internal heat is keeping the voltage juuuuust high enough to keep flying.
The instructions sound wrong… which manual or instruction sheet was that from? I’ll see if it needs correcting.
Thanks!
Matt