J-Log.eu - Forum

Hi

I'd like to know how I can format an 8GB card for use in the JLog 2.6. My existing 2GB card died - I don't know why, and its impossible to re-format it again (I tried on Mac, Windows, unix command line - no go).

I already have an 8GB card, and have *assumed* (the mother of all bad traits - yes yes), that if I can force a FAT16 partition onto the device I'll be good to go. Sure, I'll waste a god-ton of storage space, but at my local shops I can't even find a 2GB card. Ho ho - the spoils of progress.

So, the situation:
- the jlog 2.6 GW has already been upgraded for use with a HobbyWing 130a V4
- of course its been activated / licensed
- and then the 2gb SD card went and bit the bucket

What I've tried so far:

- reformatted the SD card using SDFormatter for Windows - same results as on Mac by the way.

- reformatted the SD card using SDFormatter Quick Format on Mac with *and* without logical address assignment - which is changed via the options. When done, iPartition tells me I’ve got a Windows FAT 32 partition of approx 7.4G on the card - so no surprise it fails?

- reformatted the SD card using iPartition. I made a 1.5Gb partition with 32k cluster size and 49k clusters.

Still no go - I admit, I have left the SD card completely empty - but I did expect my jlog to boot and at least create a logging directory

So my question is: *exactly* what combination of clusters / FAT partition type etc does JLog expect to encounter before it allows a boot or can write to the SD card? Or generally; should I put a .bin firmware file there?

Anyway - 3 nice flights today on the Protos V2 + HW 130a V4 - with a Jlog telling me when to come down via mAH consumption - thanks for the awesome product!

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John

Hi John!

As said, JLog supports only up to FAT16, - no FAT32, thus no card above 2GB!

You cannot mod a card >2GB for JLog by making of a partition of 2G or things like that.
Reason: The bootloader. It's sitting in an extra flash ROM section. It's size is only 4 kB. Many things have to fit into here, e.g. the decryption routine.
Thus, the FAT implementation in the bootloader has to be a minimized one. That's sufficient because the BL has only one thing to do w/ the file system: Find the flash file and read em. That's it. This is done by simply searching the main cluster for a file of a certain size, - not dealing w/ a directory. That's the reason why the file name does not matter.

The BL is able to read in FAT12 and FAT16 but NOT in FAT32. FAT32 clusters are too huge, need plenty of RAM.

Bottom line is: SD card of 2GB or less, in no case more than 2GB!

Defective card: May happen, the electronic could have died. Shit happens, Murphy is everywhere.

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The application itself wants to see a FAT16 and no different!

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Tom

So even if I make a primary partition, with < 65,536 clusters (each of 32kb) this large SD card won't work? I ask because based on your description if the disk "appears" to jlog as a < 2gb real FAT16 (i.e. < 65536 cluster) then how can it know the physical difference?

Well... once I thought I had made it.. to "shrink" a SD of >2GB by re-partitioning that it appears as 2G to JLog.

Then, later, I tried it again, several times, but it never worked. The MBR seems to be the problem to JLog's bootloader..

Ask me something else...

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Tom

OK, erm. what else... lets see...

No idea.

I solved this one by ordering a 2gb card on Ricardo. Sometimes its simpler better to stop bashing ones head hard against concrete and instead just move on... Round 1: jc: 0, jlog: 1.

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Tom

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Tom