Format SD Card Ext4 – NVIDIA Jetson TK1

The Jetson TK1 has a SD Card reader. Most Secure Digital (SD) cards come from the factory formatted as ExFat which is the most common format for Windows machines and cameras. For the card to be useful in several situations on the Jetson (like using the card as a boot disk) the SD card needs to be formatted as Ext4 for Linux to be happy. Not hard to do, you probably know how to do this already … Looky here:

For the video, a Transcend 64 GB Class 10 Flash Memory Card was formatted. We love our GBs, so try to get as many as you can afford. Currently 64GBs seem to be about right in the size to price derby.

The command itself is pretty simple, open a Terminal and execute:

$ sudo mkfs.ext4 /dev/mmcblk1p1

Note: You may want to do

$ lsblk

to check and make sure that the SD card is actually at /dev/mmcblk1p1

When the format is finished, you can mount the SD Card by clicking on the SD Card icon on the launch bar.

In Linux, you’ll see terms such as ‘mount’ and ‘unmount’ for removable media. Mounting a drive means giving the operating system access to the file system contained on that medium, in this case an SD Card. Typically you don’t think too much about the process. You pop the SD card into the card reader and it automatically opens up a window on the files on the card, mounting the SD card volume in the process. To ‘unmount’ the volume, you hit what is commonly referred to as the ‘eject button’ that is next to the SD card name in the file browser.

The eject button means different things in different situations. A CD Rom/DVD/Blu Ray disk is physically ejected from its player when that icon is clicked. In the case of the SD card, access to the file contents are removed from the operating system, but the SD card itself is not ejected from the card reader.

In order to format an SD card, the card must be unmounted before the formatting can begin. In the case where you already have files on the SD card and you want to format it, just unmount it before the format procedure.

There are other ways to format SD Cards using desktop applications, this is just one way to do so and decidedly old school.

For a more comprehensive guide for SD cards and Ext4 with performance tips and tricks, see High Performance SD card tuning using EXT4 file system.


There’s a little yellow tab on the SD card which ‘locks’ the contents. If you’re having trouble with the format process, check to make sure that the tab is in the correct position. On most cards, the unlock position is with the tab towards the top of the card, where the connector area resides.


  1. Dear

    I followed your guide and I also successed to format my SD card to ext4.
    However, when I tried to copy data to SD card, it didn’t work
    Could you give me some advices?

    Thanks you very much
    Best regards

    Nguyen Huy Hung

  2. Hello.
    Can I use SD card or small SSD hard drive as EMMC? How to install this dedicated NVidia Ubuntu R21 or later versions on that devices?

  3. Hi 🙂

    I formatted the Sandisk SD card successfully card on the Jetson TK1 but I can’t do anything to the SD card as in it is locked. I can’t copy files or add a new folder like I would do to any SD card.I have made sure that the tab on the SD is in the correct place so the contents are not locked.
    This is what I get after I used the lsblk command
    ubuntu@tegra-ubuntu:~$ lsblk
    mmcblk0rpmb 179:16 0 4M 0 disk
    mmcblk0 179:0 0 14.7G 0 disk
    ├─mmcblk0p1 179:1 0 14G 0 part /
    ├─mmcblk0p2 179:2 0 4M 0 part
    ├─mmcblk0p3 179:3 0 64M 0 part
    ├─mmcblk0p4 179:4 0 4M 0 part
    ├─mmcblk0p5 179:5 0 4M 0 part
    ├─mmcblk0p6 179:6 0 4M 0 part
    ├─mmcblk0p7 179:7 0 4M 0 part
    ├─mmcblk0p8 179:8 0 2M 0 part
    └─mmcblk0p9 179:9 0 558M 0 part
    mmcblk1 179:32 0 29.7G 0 disk
    └─mmcblk1p1 179:33 0 29.7G 0 part /media/ubuntu/de86b21d-76e0-408d-914a-76d7

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