I need to reduce the size on my Raspberry Pi boot SD card. I have read this posting Reverse the expand root FS and it embedded references, but as a near novice, I have a couple questions.

I can mount a USB memory stick on my Pi which is empty and bigger than the SD card being used to boot up the Pi. Can I run the process detailed in the above reference from that Pi, using the USB memory stick as the target for the process?

And then mount a second USB device with a micro SD card to do the final copy/creation of the new boot SD?


  • 1
    Your question is unclear. If what you want to do is copy your SD to another/smaller SD you can do this with a SD Card reader using the SD Copy utility include in Raspbian.
    – Milliways
    Dec 27, 2016 at 7:18
  • My setup for this problem is Wheezy. The Copy SD card utility is only on Jessie. I have tried to install the SD copy (PiClone) on my Wheezy but it is missing too many things. Thus, my problem and question remains, using the process detailed in the link, can I do all of it on my Pi using an external USB memory stick and external USB read/write adapter for the new SD card image.
    – RDK
    Dec 27, 2016 at 12:17

1 Answer 1


Can I run the process detailed in the above reference from that Pi, using the USB memory stick as the target for the process?

Yes, but just to be clear, you are creating the image in a file. Obviously that file has to be stored somewhere, and a USB stick should be fine for that.

In addition, because that file is then formatted as a device image containing several partitions with filesystems that are independently formatted and mounted, the filesystem on the stick doesn't have to be the same, or anything in particular. In other words, you could use a standard, preformatted (FAT32, whatever) USB stick and create the device image file there.

  • ok, I'll give it a try in the next day or so. Thanks
    – RDK
    Dec 28, 2016 at 5:12
  • If you've never done it before it is probably worth going through the basic motions once with a small test like in the original answer -- create a file, turn it into a device image with fdisk, format a partition on it, check that you can mount that, copy some files into it, unmount it, mount it again and check everything you did is still there, etc. It's really pretty simple and only takes a few minutes; I think people may get intimidated if the concepts are hazy -- then they deal with it like cargo cult magic.
    – goldilocks
    Dec 28, 2016 at 13:20
  • If it isn't totally clear to you and you have not read the other answer linked at the top that is probably worth a once through. Human errors tend to be the result of human misunderstanding. ;)
    – goldilocks
    Dec 28, 2016 at 13:20
  • GL...Have the other references and I have read through them once. I will, for sure, study them again before doing anything serious. And, I always backup my SB cards before experiments like this. Thanks for your concerns and suggestions. Today, my day has been full as I blew a power supply on my local file and web server. Lots of fun....
    – RDK
    Dec 28, 2016 at 19:52
  • goldilocks....You are correct, the process is a bit intimidating for a near novice. In your original article (Reverse Expand Pi root FS) you say "In the Raspbian image this partition is ~56 MB ... In this example, though, there isn't enough space, so I used 10 MB.". I don't see/understand this in your example? Further down you show the Partition Table to to get the starting sector for the second partition. How did you generate this table at this point in the process?
    – RDK
    Dec 30, 2016 at 8:34

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.