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question about dd command
Posted by: Andrew on 2021-02-15 19:31:04
Hello all,

I have been using scsi2sd and mini vmac and transferring images back and forth.

I think I am doing something wrong with writing sd can using dd, because the mac will not boot. When I write the same image file to the same sd card with balena etcher, it works fine.

Could you please tell me if you see something wrong with the following command? Thanks in advance

dd if=image of=\\.\Volume{......} bs=1M

Posted by: Daniël on 2021-02-15 19:41:52
This is on OS X/macOS, right? The output should be set to the disk, not the volume. Run diskutil list to see what /dev/disk# is the SD card (# would be the appropriate number), run diskutil unmountDisk /dev/disk#, then run the DD command with of=/dev/rdisk# bs=1M. That should work.

Posted by: Andrew on 2021-02-15 19:49:39
Sorry I should have mentioned it is dd for windows, and the command is executed without errors

(it says 1024+0 records in/out which is as expected for a 1gb image).

Maybe it is a bug of dd for windows.

Posted by: Daniël on 2021-02-15 20:30:05
Ah. I personally wouldn't use DD on Windows, due to the fact it's not a "native" utility for that OS, unlike on Unix and Linux based operating systems.

Posted by: johnklos on 2021-02-16 02:16:23
Ah. I personally wouldn't use DD on Windows, due to the fact it's not a "native" utility for that OS, unlike on Unix and Linux based operating systems.


Well, whether or not it's "native", Windows does all sorts of things in problematic ways that make something that should be and usually is 100% consistent and reliable in to something inconsistent.

If you were interested, you could `dd` on Windows, then `dd` on a real operating system, then compare the Windows image with the file that was supposed to be imaged, but it's up to you whether you want to figure out what's really going on. If Balena works, then that's much better than `dd` on Windows.

BTW - we can't tell you whether that `dd` command makes sense because you didn't send the command. We can't possibly know what you put in for {.....}.

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