Cold IMU temp error

Thought I’d post this again given no answers and I have to fly in two days with about -5c to -10c conditions. My IMU isn’t going above 38.6c so I’m getting a IMU low temp pre arm error. I can clear that issue if I set the temp to something lower, but that was only around 0c. Is the Cube Black done?

Obviously not a common issue, but in case someone else experiences this I think I found the issue. I was calibrating the imu temperature in case the heater couldn’t keep up with the cold flight conditions when I found my ins_acc/gyro_caltemp values were -300. That’s factory/disabled. Before firmware 4.3, the values were in the 40’s. Somehow updating to 4.3 reset them. It shouldn’t make any difference how well the heater works, but it does😂