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SD Card requirements?

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I am looking to buy another SD card for my Ultimaker printer (with Ulticontroller) and I can't seem to figure out what the size limits are, if the SD card needs to be formatted any certain way, etc



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If you buy a SDHC card and format only a 2GB FAT-32 partition, it might work. I'm not sure though as SDHC has substantial differences compared to standard SD.

Don't forget that the Ulticontroller is nowhere near a PC, it's just a small 8-bit MCU...

I could try that, got a 32GB card lying around. If I don't forget about it, I'll report back ;)


tried it, but it seems Win7 can't format an SD card with custom partition sizes... The necessary settings are not available :(

Maybe it works with some advanced disk tools, but I don't have any...

It's best to just buy a standard 2GB SD card, no SDHC or even higher tech.


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I've been looking into this myself and replied to another pre-existing post recently asking the question. I've searched the forums extensively and I have come up with a number of results but not a definitive/confirmed answer.

In one particular case, going back a while, Daid suggested that SDHC cards should *not* be used, as there was a risk of a print restarting mid-print, which could cause numerous problems if such a card was used.

I am not sure if this only applies to the ulticontroller/UM1 or stands for the UM2 as well (which in my case I am particularly interested for).

I would like to use Eye-Fi cards myself to avoid the inconvenience to me, and the wear and tear on the controller/SD card reader slot of changing cards all the time. Unfortunately these can only be found in SDHC cards these days.

A confirmed/official answer would be most appreciated and I am sure would answer more questions that I expect to see in the future, especially with the difficulty of finding non SDHC cards increasing these days.

Also, it would be good to know if SDHC cards are not supported currently if there are plans to change that? Is it a firmware/software fix or is it a hardware limitation?


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Since the Marlin firmware uses Arduino SD library to reach the SD card, the sd read capability is depended on the library. Quote from sd library official site "http://www.arduino.cc/en/Reference/SD/"

"The SD library allows for reading from and writing to SD cards, e.g.... It is built on sdfatlib by William Greiman. The library supports FAT16 and FAT32 file systems on standard SD cards and SDHC cards. It uses short 8.3 names for files."

See, both SD and SDHC should be OK. But I also know many people have problems with the SD reading. Probably it is just a "card compatible" problem. And lots of sd cards on the market are not severely follow the standard interface?

Just guess.


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I did reformat the thing, same result...

Bought it at a games shop, they use it to alter Wii stuff, and did cost €2,50.

That would be enough for a lot of gcode files otherwise the length to scroll through is endless.


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On a Mac, MacOS 10.13.3, it seems you have to format the SD card with:


* MBR partition scheme

* FAT32


I got the following to work (assuming your SD-card has "disk2", you might have to do this in your terminal.


#make sure that your SD card really is disk2
diskutil list

#If you are convinced that your sd card really is disk2
sudo diskutil eraseDisk FAT32 3D MBRFormat /dev/disk2


If you do not specify that your  SD card should be partitioned using MBR partitioning scheme, MacOs will format it using GUID scheme, which the printer cannot read. I have formatted 16GB cards this way, and they can be read by the Ultimaker 2+. Id does not seem like there is an easy way to do this in the Disk Utility anymore.




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