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Given sd_card.img that is 512000000 bytes (i.e. 488MB):

$ file sd_card.img

sd_card.img: DOS/MBR boot sector; partition 1 : ID=0xc, start-CHS (0x0,1,1), end-CHS (0xdf,15,54), startsector 63, 999873 sectors, extended partition table (last)

fdisk shows:

Selected partition 1 Device: sd_card.img1 Start: 63 End: 999935 Sectors: 999873 Cylinders: 1158 Size: 488.2M Id: c Type: W95 FAT32 (LBA) Start-C/H/S: 0/1/1 End-C/H/S: 223/15/54

I attempted to resize it with the following commands.

$ cp sd_card.img test.img

$ dd if=/dev/zero of=test_zeros bs=1 count=1 seek=2G

$ cat test_zeros >> test.img

$ sudo parted test.img resizepart 1 2.5GB

$ file test.img

test.img: DOS/MBR boot sector; partition 1 : ID=0xc, start-CHS (0x0,1,1), end-CHS (0x12f,239,61), startsector 63, 4882750 sectors

fdisk shows:

Selected partition 1 Device: test.img1 Start: 63 End: 4882812 Sectors: 4882750 Cylinders: 334 Size: 2.3G Id: c Type: W95 FAT32 (LBA) Start-C/H/S: 0/1/1 End-C/H/S: 303/239/61

Then I write the image to the 32GB SD card:

dd if=test.img of=/dev/mmcblk0 conv=fsync status=progress

When the SD card is mounted...

# lsblk

NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS mmcblk0 179:0 0 29.7G 0 disk `-mmcblk0p1 179:1 0 2.3G 0 part /run/media/mmcblk0p1

This looks promising, but df -h is not so much. This is what it shows with the original sd_card.img written to the SD card and after this modification:

Filesystem Size Used Avail Use% Mounted on /dev/mmcblk0p1 485M 159M 326M 33% /run/media/mmcblk0p1

Since lsblk displays block device size and df displays filesystem size, it suggests something is wrong with the partition.

Unfortunately, easier methods do not work well with FAT32 partitions, which I am limited to. After installing necessary libraries, I tried sudo gparted sd_card.img but it did not work, various operations instead showing sd_card.img1 and stating the file did not exist.

Any suggestions on what the issue in my procedure might be or otherwise how to do this properly?

Note: GNU Parted 3.4

Update

Following @eyoung100's suggestion, I wrote my original sd_card.img to the SD card and then used the command line tool parted, which is installed with GParted, in an attempt to expand the free space.

sudo parted

select /dev/mmcblk0

print free

Number Start End Size Type File system Flags 1 32.3kB 512MB 512MB primary fat32 lba 512MB 31.9GB 31.4GB Free Space

resizepart 1 100%

print free

Number Start End Size Type File system Flags 1 32.3kB 31.9GB 31.9GB primary fat32 lba

quit

Because GParted does not do anything until it is told to Apply changes, I wonder about quitting without saving anything, but when I boot from the SD card the changes are displayed so I think parted is more of a "gloves off" version where you really need to know what you are doing.

# df -h

Filesystem Size Used Avail Use% Mounted on /dev/mmcblk0p1 485M 172M 313M 36% /run/media/mmcblk0p1

# lsblk

NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS mmcblk0 179:0 0 29.7G 0 disk `-mmcblk0p1 179:1 0 29.7G 0 part /run/media/mmcblk0p1

So as previously mentioned, the changes I make in parted are actualized, but they are not found in usable space or the output of df -h. The actual size of the FAT32 partition remains ~488MB.

# fdisk -x /dev/mmcblk0

Disk /dev/mmcblk0: 29.72 GiB, 31914983424 bytes, 62333952 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0xe847ab93 Device Boot Start End Sectors Id Type Start-C/H/S End-C/H/S Attrs /dev/mmcblk0p1 63 62333951 62333889 c W95 FAT32 (LBA) 0/1/1 1023/254/63

When this sd_card.img is inserted into another device to boot of off, it gets mounted by that device. I am not sure how yet, but I see this>

# cat /run/systemd/transient/run-media-mmcblk0p1.mount

# This is a transient unit file, created programmatically via the systemd API. Do not edit. [Unit] After=dev-mmcblk0p1.device BindsTo=dev-mmcblk0p1.device [Mount] What=/dev/mmcblk0p1 Options=umask=007,gid=6 [Unit] [email protected] [email protected]
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    GParted does not work on individual files (that I know of). Try just gparted then input your sudo password and let gparted determine the available devices and complete your task. Commented Jan 24, 2024 at 16:17
  • @eyoung100 when I open gparted it shows me the hard drive in the graphical view and provides options. With gparted sd_card.img it shows me the graphical view of my .img file with accurate information. Commented Jan 24, 2024 at 18:07
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    Well, I learned something new. Thanks! When the SD Card is mounted, and you open with just gparted can you see your SD card in the device list on the top left? Commented Jan 24, 2024 at 19:38
  • Yes, it is the only device listed. And it displays as expected for sd_card.img and test.img, with test.img showing 2.33GiB size and 152.1MiB unallocated after the first partition. Commented Jan 24, 2024 at 19:57
  • And what happens when you click the partition you want resized and attempt to resize it? Do you have an ! next to that partition? As a hunch, you can't resize a partition if: 1) It's currently mounted, or 2) The SD card is in a size adapter. The adapters mark the card as read-only. In this case, a screenshot would be warranted. Commented Jan 24, 2024 at 20:13

1 Answer 1

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In an effort to unconfuse us both, I'm now writing this as an answer.

Confusion

You either have the original image still mounted when you finish, or you have improperly resized the original image.

Starting Fresh

  1. Unmount all your SD Cards.
  2. Follow this command line tutorial, or use this tool/Etcher linked from that tutorial to write the small 500 MB image file to your Bigger 32GB SD Card or other device.

Note: Even though the tutorial above was written for a Pi based OS, the instructions apply for all SD Cards. Also note that I'm not rewriting the commands contained there, so confusion is minimized.

  1. You should now have an extracted image file of 488MB written to a 32GB card, leaving about 31.5 GB

If I'm understanding correctly, you (the OP) would like to expand the partition so that it fills the entire 32 GB

Expanding the Partition

  1. We no longer need to worry about creating a second image because we wrote the original small image to the bigger SD Card in step 2 above.
  2. Start GParted.
  3. Remove and Reinsert the 32GB SD Card, so that GParted rescans the device nodes and refreshes.
  4. You should see the small 500GB Partition on the SD Card surrounded by a teal colored box on the left side of the bar, and a whole bunch of Gray on the right with the words Free Space.
  5. Drag the Arrow at the end of the teal box all the way to the end of the Free Space (as far right as you can).
  6. Press the Checkmark in the Toolbar to Apply/Save the change.

Let me know if this is what you wanted to achieve. If not, you need to provide more clarity or detail in your question.

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  • A main point of divergence is that the only Linux machine I can insert an SD card into is headless so I can only ssh into it and I am not looking to set up an x11 session of some sort. That is why my question and responses all involve parted, rather than GParted. But parted is part of GParted so the same operations should work. I updated my question with details on how following your steps went. As mentioned previously, it is for some reason not working as expected. Commented Jan 25, 2024 at 19:16
  • @fm_user8 gparted is a software on its own, not merely a frontend to parted. parted no longer resizes filesystems; resizepart merely resizes the partition. you can either use a very old version of parted that still resizes fat32 on its own (resize command instead of resizepart); or try a different tool like fatresize. Commented Jan 25, 2024 at 20:01
  • Knowing it is headless does help. After the partition table looks the way you want resizepart1 100% is correct, along with quit which should save the changes. Did you receive any status message from parted about updating fstab? See here Commented Jan 25, 2024 at 20:07
  • @eyoung100 yes, it does mention updating fstab, but this SD card is used to boot another device so the local fstab would not apply. After booting the other device, that device mounts the SD card, so maybe something on that device needs to be changed in some fashion, though from what I have seen it is automounted so the size seems to be set automatically. mount on that device shows: /dev/mmcblk0p1 on /run/media/mmcblk0p1 type vfat (rw,relatime,gid=6,fmask=0007,dmask=0007,allow_utime=0020,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro) Commented Jan 26, 2024 at 22:02
  • Older versions of parted do not support fs.type=vfat. Try type fat32 Commented Jan 26, 2024 at 22:13

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