Found the tiny fan on top of the plastic plate to which the camera assembly attaches. After the battery is turned on, it spins up within 20 seconds or so. You can see it spin up with a flashlight. Great suggestion of using an external fan during updates. Might even put it near the AC next time during the update, in preparation for the IMU calibration after. I have arrows and notations all over my gimbal guard to put it on correctly, but that isn't the issue. To install it properly, it still needs to be put on with enough force to secure the tiny part at the top over the alignment aid, by pushing it tightly against the gimbal. Similar pulling force is needed to remove it. If you transport the P3P gently in the backseat of your car, in a case which is only held horizontally, the gimbal sustains less torque than the installation and removal of the gimbal guard requires. For any other travel, it's worth the effort, though. Is there any warning, in the app, during power up that the gimbal guard has not been removed, if you forget to do so, like the one warning you that no micro SD card has been inserted?