MicroSD Image Backup Problem

[BigG2017]

After making some changes to my Armbian setup on the Odroid xu4, I decided to use the Win32DiskImager tool on my Win10 machine to make a bootable image from the microSD card.  However, I've now tried two different micro sd cards (a Samsung and a Sandisk) for the backup, but Win10 tells me that it doesn't recognize the file system.  It asks me if I want to format the cards.  Obviously I don't, because neither would be usable my Odroid xu4.  Any idea why I can't backup these Armbian xenial images?  Is there a comparable tool on Linux (I have Fedora on another machine) that can make the backup?  (I pulled this issue from another thread where it really didn't belong.)  Thanks.

[BigG2017]

Well, I may have found an ubuntu post that helped answer my question/solve my problem:

https://askubuntu.com/questions/227924/sd-card-cloning-using-the-dd-command

states:

Insert the original sd card and check the name of the device (usually mmcblkX or sdcX):

sudo fdisk -l

In my case the sd card is /dev/mmsbkl0. Now you have to unmount the device:

sudo umount /dev/mmcblk0

Now to create an image of the device:

sudo dd if=/dev/mmcblk0 of=~/sd-card-copy.img

This will take a while.

Once it's finished, insert the empty sd card. If the device is different (USB or other type of sd card reader) verify its name and be sure to unmount it:

sudo fdisk -l
sudo umount /dev/mmcblk0

Write the image to the device:

sudo dd if=~/sd-card-copy.img of=/dev/mmcblk0

Those directions appear to have made a .img file using my Fedora 25 machine; however, I have not tried to write that image to a micro sd card to test it.  Waiting until that's required!

[tkaiser]

4 minutes ago, BigG2017 said:

I have not tried to write that image to a micro sd card to test it.  Waiting until that's required!

 

That's why 'backups' are failing. Since people don't test.

 

Besides that using dd is always wrong (but this will never change since the whole Internet is just copy&paste of outdated/wrong information over and over again). Cloning SD cards should be done using ddrescue and re-imaging should always happen with Etcher. To get the idea simply use Armbian's search function and search for 'ddrescue'.

[BigG2017]

I'll probably "wipe out" something before too long...testing could happen sooner than expected!  Anyway, thanks for the follow-up and recommendations.  My command line experience is very limited at this point, so I'm certainly looking for help as I gain more knowledge.  I'll take a look at ddrescue and Etcher.