Internal Storage and Flight Data Question

[NoVaMavicPilot]

Greetings all,

This is a great forum and glad to be here. I've owned my MP2 for a couple months now and have done around 30 successful flights. I also received my 107 cert. A common theme on here, and an issue I've personally noted, is that DJI leaves a lot of obvious questions unanswered. I've had to learn the answers on this forum or on Youtube.

I use Airdata and synch flight data after every flight. I try to clear the drone's internal storage as regularly as possible but am unclear what the software does with the flight data if not cleared. Does new flight data overwrite old flight data only when the internal storage reaches near max? Does the listed internal storage usage include both the stored flight data and media? Thanks!

 

[quaddamage]

This page says the "H3 Eagle" chip is responsible for both video encoding and flight control:

WM240 Core Board

Tools for handling firmwares of DJI products, with focus on quadcopters. - o-gs/dji-firmware-tools

github.com

(see "programming" chapter)

This suggests that both media and flight logs are stored on the eMMC connected to H3 chip - so it's single storage.

For how things are organized within that one storage - I don't know. If I was designing such system, I'd create separate partitions for flight logs and media. So both would have separate amount of free space.

I've heard some people have dumps of the M2 eMMCs; this could be checked on such dump.
To make such a dump, one needs to have related chip (Eagle and/or Leadcore) rooted.

In previous platforms, old flight logs were automatically deleted when there was little space left of flight logs storage chip.

 

[slup]

For DJI crafts you usually have 3 different flight logs in 2 types ... the 2 types ends either with .TXT or with .DAT.

The mobile device stored .TXT log (records from motor start to stop)
... is only stored in the screen (mobile) device you flew with ... it contains mainly telemetry transmitted from the aircraft to the RC at 10 Hz in a few hundred data fields. These logs don't include any raw sensor data - only the IMU solutions that are the output from the sensor fusion algorithm. They also include battery data, gimbal and camera data, flight status and error flags, but no motor data. This is the one that are synced to Airdata.

Then you have the craft stored .DAT log (records from power on to off)
... these logs contain the most comprehensive data, logged at the highest rates and includes numerous boot sequence, sensor calibration and diagnostic data in the flight event stream. There are also hundreds of data fields, many of which are flags or diagnostic computations of unknown types, probably understood only by DJI. However, among these are the raw and processed sensor data and the IMU solution for aircraft attitude, position, velocity and heading, together with battery and motor data, recorded at rates varying from 5 Hz to 200 Hz. These logs aren't stored in the same user accessible memory area as photos or vids you have stored on the craft internal memory ... you can't wipe the .DAT log memory area. The logs there will be over written when that area is full. You can only access those craft .DAT logs through DJI Assistant 2.

Unfortunately, on recent DJI models (Mavic Air, Mavic 2, Mavic Mini and Mavic Air 2 and Mavic Mini 2) the decryption keys are hidden, and so those are not readable except by DJI.

Lastly the mobile device stored .DAT log (records from power on to off)
... These contain a subset of the craft .DAT logs, including most of the raw sensor data, recorded at a lower data rate of 10 Hz. Not as good as the craft .DAT logs, but nearly as good for most needs.


The 2 mobile stored (.TXT & .DAT) can be accessed by connecting your mobile device to a computer ... with DJI GO4 the .TXT is stored in DJI » dji.go.v4 » FlightRecord. with DJI Fly they are in DJI » dji.go.v5 » FlightRecord. The mobile stored .DAT log are in a subfolder, MCDatFlightRecords, in the folder that contains the .TXT logs.

Both of the mobile stored logs can be deleted in the same way you delete all other files on your mobile device.

 

[NoVaMavicPilot]

Thank you. When I load the SD card to my PC, I see it copies over the attached file folders. I am just going to delete DCIM media files to maintain storage capacity. I am hesitant to delete anything else safely. Suggestions?

 

[slup]

Is this SD card from your mobile device or is it the one you have in your craft?