Post 5:
This is my conclusion after three or four days testing with A2 FW 2.7
I was satisfied enough with FW 2.4 and because there have been no issues have not connected the iPhone 5S for some time. I decided to do a system check and discovered that the DJI App no longer opened on my iPhone 5S. Evidently the change to iOS 9 meant that the DJI has to be updated to remain compatible.
However, the updated DJI App is not compatible with FW 2.4.
This is why this whole process started. With an international assignment coming up that puts me in a remote location where I do not want to have to lug around the Macbook, I need to be able to use the iPhone to adjust parameters if that becomes necessary.
The issues I encountered with FW 2.7 are summarised below. Note that I also downgraded from 2.7 to 2.6 at one point, just to see if the iPhone App for that firmware version remembered the deselected Airport Restriction. It did not and so, as there did not appear to be any other potential benefits, I returned to 2.7.
1. Retracts confusion
There was a peculiar confusion regarding how the system read the retracts Up/Down position depending upon whether they are connected or not during the configuration process. I still do not fully understand what was going on but suffice to say, it does work eventually if you keep everything connected during configuration. Just remember to support the drone when verifying the retract operation so that it doesn't come crashing down on your gimbal.
2. Airport Restriction
The Airport Limit restriction can be deselected after agreeing to the safety statement that pops up. However, the iPhone App does not remember your selection and every time the App is started the Airport Restriction is back in place. The DJI Assistant on the computer, however, does remember your selection. The problem here is that I am not sure which of the two interfaces to believe. The Airport Restriction check box option did not appear at all on early Windows Assistants with a Macbook running Parallels and the restriction could only be lifted using the valid iPhone DJI App at the time.
So at that time the iPhone app was the one to trust. Now though, the computer Assistant appears to be more bug-free than the iPhone App. But still, which one to trust?
3. Low Voltage Warnings
FW 2.7 does not read battery voltages in the same way as before. Specifically it appears to be conservative in the extreme with its low voltage warnings. In order to end up with 10 - 12% LiPo power remaining, the second low voltage warning has to be set stupidly low at 20.0v. This equates to 3.33333...v per cell and would be considered as foolhardy. That is knocking on the door of LiPo destruction - with every flight!
Previously, my second low voltage warning used to be set at 3.4v or 3.45v per cell, with an audible alarm set at 3.6v per cell in order to give enough time to land without a panic before the second level warning kicked in and landed the MR automatically. End of flight LiPo cell voltage was typically 3.7v per cell.
So, with regard to the low voltage warning settings, take the time to do flight tests at various settings with known batteries and do use audible low voltage alarms to prevent accidental destruction of a LiPo pack.
In fact, always use an audible on each flight pack anyway.
4. IOC / Carefree
FW 2.7 gives 'lumpy' flight in CareFree mode - IOC in DJI speek. With 'Home Point' selected it all works as it should, i.e. select Home Point, yaw 90° left and push Elevator forward and the drone will move to its right, away from you as if travelling forwards under normal flight mode.
But, if you then want to move it to the right, for example, you must bring it to a stop first. Otherwise, the drone will do a heart-stopping lurch as it sorts itself out for the new direction. It did not behave like this with FW 2.4.
So, other than those four points, FW 2.7 appears to be solid enough in flight.
