LOGs inside the SD card - I WANT TO KNOW

[m80116]

I think I have the right to know following the new events for reporting to the best of my knowledge correct and accurate information what is happening with the Mini.
It all started in here Formating

Noted people of this forum said: -There are no flight logs on your SD card-.

Now, can you explain to me and to all the gentlemen out here what is the .log located inside my Mavic Mini microSD card?
It's called fc_log.log and it's stored inside the folder /root/MISC/LOG/flylog/

It keeps popping up every time I fly (well, actually after I am done flying, just to be clear)
Presumably under any reasonable assumption it's a flight log generated by the Flight Controller (hence fc_log) of the Mavic Mini.

Also of relevance in the LOG folder there are the following files:

camera_log.log
linux_log.log

Not only that I also have an email received in response from a DJI Support representative asking me to retrieve data from the Mavic Mini, suggesting that logs stored in the microSD card contain "flight data" as clearly stated in the mail. Doesn't flight data sound quite the same as "flight log"... end even if it were just "data" without any identifiable fligth path, can't it just be classifed as a "fligt log" as it is gathered during flights?

Now obviously I don't have any way of reading that data but under my best educated guess that data (/root/MISC/LOG/flylog/fc_log.log) is exactly a flight log, along with system (linux_log.log) and camera data (camera_log.log). It's exactly the kind of data DJI needs when the telemetry fails and the Remote Control is unlinked and not receiving feedback anymore. Data that supplements the missing telemetry in the Mobile Device to exactly track down everything concerning a flight, being practically a black box, the Flight Recorder of the aircraft.

Now... if you have some other ideas that you want to express politely you're welcome to come forward because nobody is born learned. You may have a different one than mine but you'd really need to substantiate your claims if you want to demonstrate there's no flight data in the SD card logs.

 

[Meta4]

It's exactly the kind of data DJI needs when the telemetry fails and the Remote Control is unlinked and not receiving feedback anymore.
Data that supplements the missing telemetry in the Mobile Device to exactly track down everything concerning a flight, being practically a black box, the Flight Recorder of the aircraft.

What you are describing is stored on a different SD card glued inside the drone.
It's an SD card that you cannot access or delete files from.
Those are the files DJI investigate if you return the wreckage to them.

 

[m80116]

That would be in the SD card domain again... however I understand what you probably wanted to point out: a soldered flash memory chip.

I expected some others to step in (we'll see), you're telling me the same as in the other thread, without substantiating your claims.

How am I supposed to believe such generic claim when I have a file called fc_log.log in a LOG folder on the microSD. MM doens't have internal user storage, they would have to store that information alongside the firmware and still I couldn't understand why you should rely on a broken board (let's say water damaged or cracked) in case of an accident? I'd find it logical to withdraw the "black box" (the microSD) from a wreckage, otherwise they'd have to de-solder the BGA memory chip and read it... doesn't make sense when you have plenty of space in a dedicated removable memory card.

 

[Meta4]

How am I supposed to believe such generic claim

I expect that you won't believe anything I write, that's your nature.

That would be in the SD card domain again... however I understand what you probably wanted to point out: a soldered flash memory chip.

I haven't opened a Mavic to see what's in there but other DJI drones have an SD card glued inside, that functions as a black box recorder.
Use Google and search for DJI Internal SD card and you can pick up the trail from there.
DJI has never asked anyone for their camera SD card for flight data.

 

[scro]

DJI Mavic Mini Teardown : What's inside?

Buy your Mavic Mini today! It has become tradition here at RC Geeks to tear apart any new tech we get in. We love to see how the manufacturer has put it together and our engineers get first hand experience on how future repairs might be carried out. We also know it can be a useful resource for...

www.rcgeeks.co.uk

No "hidden" SD cards found inside the Mini on that teardown, unlike on some of the larger Mavics:

Micro SD Card Hidden Inside The Mavic Pro

Look. There's an Sandisk Micro SD card that's glued inside of the Mavic Pro. It's where all of the flight controller data gets recorded to. Neat.

forum.dji.com

Quite likely the idea for a dedicated, glued in SD card on the mini was dropped due to the weight target of <250g

Makes you wonder if the onbard DAT file is stored on the user's SD card, or also on one of the soldered in chips?!

 

[Zbip57]

What you are describing is stored on a different SD card glued inside the drone.
It's an SD card that you cannot access or delete files from.
Those are the files DJI investigate if you return the wreckage to them.

The log files described by m80116 are contained on the Mini's normal removable microSD card. It's the same card on which your photos and videos are recorded. You can access or delete files from that removable card.

If you pull the microSD from the Mini and plug it into your computer, you can format the card on your computer. A quick format merely marks all files deleted and verifies the file index is cleared. A full format takes longer and over-writes each file block. If you then re-insert the newly formatted blank microSD card back into the Mini and power it up, the Mini will automatically re-create its folder structure on the microSD card.

If you format the card via the Fly app, with the card installed in the Mini, the microSD card will be quick formatted and the folder structure will be refreshed.

Here is what the folder structure looks like on my microSD card. I renamed my card "MavicMini" so as not to confuse it with my other cameras, etc. And I added a txt file in the root directory with my contact information, in case anyone ever finds the card.

In the DCIM folder, there is a subfolder 100MEDIA which contains the Mini's camera recordings. Note there also is a "hidden" folder called MISC.



Expanding the MISC folder shows more hidden folders, one called LOG which contains:
camera_log.log
linux_log.log



In the LOG folder there is another sub-folder called flylog, which contains:
fc_log.log



It is interesting to note that each of my log files are exactly the same size as those shown in the image posted above by m80116, with the only difference being the file date. The dates seem to update every time the Mini is powered up.

I cannot verify whether or not these contain "flight logs", since I cannot read the files. But clearly something is being logged on the removable microSD card.

 

[EyesWideShut]

@Zbip57 - Clearly explained. Thank you!

 

[Meta4]

The log files described by m80116 are contained on the Mini's normal removable microSD card.
It's the same card on which your photos and videos are recorded. You can access or delete files from that removable card.

Read his post again and you'll see that he said:

It's exactly the kind of data DJI needs when the telemetry fails and the Remote Control is unlinked and not receiving feedback anymore.​

Data that supplements the missing telemetry in the Mobile Device to exactly track down everything concerning a flight, being practically a black box, the Flight Recorder of the aircraft.​

None of that is found on your removable SD card with your image files.
But it is found on the hidden internal SD card (at least on DJI models before the Mini).
And you cannot access it, format it, delete it etc.

 

[maelstrom]

None of that is found on your removable SD card with your image files.

If that's the case, what does the flylog folder on the microSD card contain then?

 

[Meta4]

If that's the case, what does the flylog folder on the microSD card contain then?

Nothing that anyone's ever found a use for.

 

[Zbip57]

Read his post again and you'll see that he said: [...]

I have read his post. He specifically asked,

what is the .log located inside my Mavic Mini microSD card?
It's called fc_log.log and it's stored inside the folder /root/MISC/LOG/flylog/

He makes the "reasonable assumption it's a flight log generated by the Flight Controller (hence fc_log) of the Mavic Mini."

I share his curiosity. The txt and dat flight logs stored on your phone or tablet device by the Fly app cease recording data whenever the signal from the Mini is lost. It would be interesting to know what exactly is recorded in those onboard log files on the removable microSD card.

"can you explain to me..., presumably under any reasonable assumption..., obviously I don't have any way of reading that data..., if you have some other ideas..."

I think that naming the file fc_log and placing it a folder called flylog indeed makes it a reasonable assumption that the file contains information relating to flight logs.

He, and I, are both curious to know if anyone has the means to decipher those files. Meta4, you on the other hand seem quite convinced that these files don't exist on the removable microSD card (obviously false), and even if they did exist they couldn't be accessed or deleted (also false), or if they did exist at all they would only be stored on a hidden internal glued SD card (which doesn't exist in the Mini).

None of that is found on your removable SD card with your image files.
But it is found on the hidden internal SD card (at least on DJI models before the Mini).
And you cannot access it, format it, delete it etc.

The files quite clearly do exist on the same microSD card as the Mini's recorded images and videos. So we're still curious to know what they contain. To which your response seems to be:

Nothing that anyone's ever found a use for.

So, it's not worth asking for information because you believe the Mavic Mini's onboard log files have somehow been determined to contain nothing useful. And you know that how exactly, since you keep insisting the files are non-existent. inaccessible, and un-deletable?

 

[Meta4]

He makes the "reasonable assumption it's a flight log generated by the Flight Controller (hence fc_log) of the Mavic Mini."

I don't share your assessment that he made a reasonable assumption.
I believe his assumptions are rather questionable.

you on the other hand seem quite convinced that these files don't exist on the removable microSD card (obviously false),
and even if they did exist they couldn't be accessed or deleted (also false), or if they did exist at all they would only be stored on a hidden internal glued SD card (which doesn't exist in the Mini).

I haven't said anything to suggest that at all.
I have no idea what gave you that idea.
Of course the files exist .. anyone can see them on the SD card and they regenerate every time you put a clean card in the drone.
And of course I know that those files can be accessed and deleted.
I've done it myself.

I've referred to completely different files that do contain the flight data that DJI rely on for incident investigations.
Those are on a hidden card inside DJI drones.
I suggested the OP might educate himself about this in post #4 and told him how.
Perhaps you could as well.
I don't know if the Mini has a similar system or what it might be.
But I do know that the files on the card with the images is the same for the Mini.

If you can work out what those files on the SD card are, good luck to you.
As far as I know, no-one has ever found out anything about them.

There's a project for you.
Come back and tell me when you find out what they really are instead of making so many assumptions.

 

[Deleted member 103366]

I am not attempting to ignite a war and I am not posting in support of any side but this peeked piqued (whoops) my interest.
I found the log.log file on my mini's removable mSD card and copied it to my pc. Its properties show it to be a text file so I tried opening it with notepad, firefox and probably wordpad, none could open it, I tried changing the extension to .rtf, no joy.
I then changed the extension to .DAT and threw it at DatCon 3.7.5, it took some time but it seems to have worked in that, on my "desktop", I now have
23/06/2020 14:57 128,226 fc_log.config.txt
23/06/2020 14:57 2,778,499 fc_log.csv
23/06/2020 14:57 765 fc_log.kml
23/06/2020 14:57 17,281 fc_log.log.txt
23/06/2020 14:57 72,952 fc_log.recDefs.txt

fc_log.csv opens successfully with MS works, MS? Excel complains.
The csv opens as a 256 column spreadsheet, I find what appears to be dates in column aw (49) , and what looks like times in column AX (50). If these are dates and times it looks like the records spans a couple of minutes.

Datcon was installed to do this so the output can not be a legacy of running on another dat file,

As I said at the start this is not in support of any individual, it is simply what I found. I will leave it to more experienced people to determine if their files are 'flight logs' or small sections from one or several etc. etc.

 

[Zbip57]

I don't share your assessment that he made a reasonable assumption.
I believe his assumptions are rather questionable.

An example of an un-reasonable assumption would be that DJI automatically creates and updates a file named camera_log.log on your microSD card only for the purpose of storing your grandmother's most recent cookie recipes.

A reasonable assumption is that a file named camera_log.log might contain some logged information concerning the camera. Similarly, the fc_log.log stored in the flylog folder might contain something to do with a flight controller log. Sure, it is questionable. That's precisely why we are asking the question.

Rather than providing any useful response whatsoever, you keep referring to "completely different files" on a hidden card.

I've referred to completely different files that do contain the flight data that DJI rely on for incident investigations.
Those are on a hidden card inside DJI drones.

I also have some completely different files stored in a filing cabinet in my office. Those are equally irrelevant to the question being asked here.

What is the purpose of the log files specifically stored on our removable microSD cards in the Mavic Mini?

There's a project for you.
Come back and tell me when you find out what they really are instead of making so many assumptions.

Thanks, you're certainly a big help. You're basically saying you know nothing, can't answer reasonable questions, and want us to go away to figure it out for ourselves. But then you'd like us to come back and educate you with the answers? Wow, now that's some questionable reasoning.

 

[Meta4]

An example of an un-reasonable assumption would be that DJI automatically creates and updates a file named camera_log.log on your microSD card only for the purpose of storing your grandmother's most recent cookie recipes.

I don't believe the OP to be a reasonable person at all and I'm wondering about you.
It seems to me that you haven't taken in anything of what I've made an effort to explain.
I don't need the kind of aggravation that's evident in your posts.
I haven't anything else to say to you.

 

[Zbip57]

There are no flight logs on your SD card.

None of that is found on your removable SD card with your image files.

Meta4, you seem quite convinced that these files don't exist on the removable microSD card

I haven't said anything to suggest that at all.
I have no idea what gave you that idea.
Of course the files exist .. anyone can see them on the SD card and they regenerate every time you put a clean card in the drone.
And of course I know that those files can be accessed and deleted.
I've done it myself.

Phew. I'm sure glad that's cleared up then.

 

[Zbip57]

Using the latest version 3.7.6 of DatCon, I followed the clever advice of PhiliusFoggg.

I found the log.log file on my mini's removable mSD card and copied it to my pc. [...] I then changed the extension to .DAT and threw it at DatCon 3.7.5, it took some time but it seems to have worked [...] fc_log.csv opens successfully with MS works, MS? Excel complains.
The csv opens as a 256 column spreadsheet, I find what appears to be dates in column aw (49) , and what looks like times in column AX (50). If these are dates and times it looks like the records spans a couple of minutes.

It took a very long time, but DatCon eventually generated a fc_log.csv file for me. Excel 2010 then took another long time but ultimately opened to display that file.

In my case the Excel spreadsheet spans columns A,B,C,D...AA,AB,AC...AAA,AAB,AAC...all the way out to column BCM (that's 1443 columns!). And it contains rows of data all the way down to row 127452.

As PhiliusFoggg described, columns AW, AX, and AY contain:
GPS(0);Date, GPS(0):Time, GPS:dateTimeStamp

Vast amounts of flight data are displayed from my last eight flights:
2020-04-28 T22:00:55Z - T22:34:35Z --- 34 minutes (2 flights)
2020-04-29 T21:49:38Z - T21:58:17Z --- 09 minutes
2020-05-02 T13:26:03Z - T13:38:24Z --- 12 minutes
2020-05-14 T15:35:30Z - T22:51:48Z --- 16 minutes
2020-06-05 T14:48:32Z - T14:50:01Z --- 02 minutes
2020-06-14 T21:28:51Z - T21:35:42Z --- 07 minutes
2020-06-16 T17:00:16Z - T17:05:30Z --- 05 minutes

 

[sar104]

I am not attempting to ignite a war and I am not posting in support of any side but this peeked my interest.
I found the log.log file on my mini's removable mSD card and copied it to my pc. Its properties show it to be a text file so I tried opening it with notepad, firefox and probably wordpad, none could open it, I tried changing the extension to .rtf, no joy.
I then changed the extension to .DAT and threw it at DatCon 3.7.5, it took some time but it seems to have worked in that, on my "desktop", I now have
23/06/2020 14:57 128,226 fc_log.config.txt
23/06/2020 14:57 2,778,499 fc_log.csv
23/06/2020 14:57 765 fc_log.kml
23/06/2020 14:57 17,281 fc_log.log.txt
23/06/2020 14:57 72,952 fc_log.recDefs.txt

fc_log.csv opens successfully with MS works, MS? Excel complains.
The csv opens as a 256 column spreadsheet, I find what appears to be dates in column aw (49) , and what looks like times in column AX (50). If these are dates and times it looks like the records spans a couple of minutes.

Datcon was installed to do this so the output can not be a legacy of running on another dat file,

As I said at the start this is not in support of any individual, it is simply what I found. I will leave it to more experienced people to determine if their files are 'flight logs' or small sections from one or several etc. etc.

Using the latest version 3.7.6 of DatCon, I followed the clever advice of PhiliusFoggg.

It took a very long time, but DatCon eventually generated a fc_log.csv file for me. Excel 2010 then took another long time but ultimately opened to display that file.

In my case the Excel spreadsheet spans columns A,B,C,D...AA,AB,AC...AAA,AAB,AAC...all the way out to column BCM (that's 1443 columns!). And it contains rows of data all the way down to row 127452.

As PhiliusFoggg described, columns AW, AX, and AY contain:
GPS(0);Date, GPS(0):Time, GPS:dateTimeStamp

Vast amounts of flight data are displayed from my last eight flights:
2020-04-28 T22:00:55Z - T22:34:35Z --- 34 minutes (2 flights)
2020-04-29 T21:49:38Z - T21:58:17Z --- 09 minutes
2020-05-02 T13:26:03Z - T13:38:24Z --- 12 minutes
2020-05-14 T15:35:30Z - T22:51:48Z --- 16 minutes
2020-06-05 T14:48:32Z - T14:50:01Z --- 02 minutes
2020-06-14 T21:28:51Z - T21:35:42Z --- 07 minutes
2020-06-16 T17:00:16Z - T17:05:30Z --- 05 minutes

Nice work. That's a complete departure for DJI - the file that you are looking at (fc_log.log) appears to be a full aircraft DAT file and it is readable, which hasn't been the case since the Mavic Pro. The DatCon conversion uses the wrong clock speed (4.5 MHz rather than 7.9 MHz), but other than that it looks pretty good.

On my aircraft it appears to be just the most recent flight, being overwritten on each power up, but getting access back to the aircraft DAT is very significant. I'll need to take a closer look.

@BudWalker

 

[BudWalker]

Where is the LikeX10 button when you need it? Thank you @m80116 for persisting in this despite intensive public ridicule. @PhiliusFoggg and @Zbip57 also made key contributions. Especially the business about renaming it to fc_log.DAT and then waiting for DatCon to finish.

The structure of this .DAT is different from previous versions. It appears that it's always a 512 MB file with the actual data occurring somewhere in the middle. The reason DatCon 3.7.6 is so slow is that it checks and then rejects all of the filler in the .DAT. Coincidentally the changes I'm currently making to DatCon make this much faster.

In the next version I'll try to include the changes necessary to make full use of data in this new .DAT structure. Some of those changes may have to wait for subsequent versions.

 

[Deleted member 103366]

I'd rather not get drawn into the argument, I am not a participant in it.

As I said this peeked piqued (whoops) my interest and I just investigated (because I hate being locked out of a file simply because win does doesn't like the extension etc.
It's like being told I can't look at a book written in Klingon just because I wont understand the writing. If I don't understand the writing there are always the pictures to look at.)

I am not siding with anyone concerning this matter