RUT955 SD Card

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Main Page > RUT Routers > RUT955 > RUT955 Manual > RUT955 SD Card

This chapter provides a description on how to correctly insert a SD card into a RUT955 device.

The information in this page is updated in accordance with firmware version RUT9_R_00.07.06.11.


Before installation, make sure your SD card is compatible with RUT955 devices:

  1. Maximum supported (tested) SD card capacity is 64GB.
  2. Supported (tested) formats are: FAT32, NTFS, ext2, ext3, ext4.
  3. SD cards with a fixed 1.8V voltage are not supported. Make sure your memory card supports 3.3V by referring to manufacturer's documentation.
  4. The device is compatible only with microSD size memory cards.

Sd card measurments.png

RUT955 disclaimer

Note: Due to hardware limitations, RUT955 devices do not support firmware flashing while an SD card is inserted into the device. To successfully perform a firmware upgrade, it is required to remove the memory card first. Otherwise there is a high risk of data and configuration loss.


Make sure device is powered off before inserting SD card!

SD card insertion
1 Disconnect from power and remove back panel from the device, pull out PCB board to reach SD card socket
2 Slide SD card holder forward to open it
3 Carefully insert SD card into the socket (pay attention to SD card and socket cutouts)
4 Close SD card socket holder and slide it backwards until it locks
5 Slide back PCB into device housing and attach back panel. Now you can power your device and use it.
Networking RUT955 manual sd card.png

Networking device manual sd card closeup.png


Once device is booted up with an SD card installed, you can confirm it is recognized by navigating to USB Tools WebUI page. Under Mounted File Systems the SD card should be visible:

Networking device manual sd card mounted file systems.png

You may now use various functionality found in USB Tools with the SD card instead of a USB device.

If you are having trouble with the device recognizing your SD card, please refer to the Troubleshooting section below.


  1. Double check the SD card is compatible with RUT955 devices.
  2. Make sure the SD card is not corrupted. We recommend formatting it before first installation.

Formatting SD card using device

If you are unable to format the memory card using other means, it is possible to do it directly on RUT955 device.


  1. Device must have WAN access.
  2. SD card must be recognized by the filesystem.


  1. Connect to device's CLI.
  2. Use command ls /dev/ | grep mmc to display recognized memory cards:
  3. root@Teltonika-RUT955:~# ls /dev/ | grep mmc
    mmcblk0p1 ← SD card
  4. Once confirmed the SD is recognized, we may start the formatting procedure:
  5. Run commands opkg update and opkg install e2fsprogs to download required tools.
  6. Unmount the SD card with command umount /dev/mmcblk0p1
  7. Start formatting with command mkfs.extX /dev/mmcblk0p1 where X is either 2 (for ext2 format), 3 (for ext3 format) or 4 (for ext4 format).
  8. A successful format procedure should look like this:
  9. root@Teltonika-RUT955:~# mkfs.ext2 /dev/mmcblk0p1
    mke2fs 1.45.6 (20-Mar-2020)
    /dev/mmcblk0p1 contains a ntfs file system labelled '64gb'
    Proceed anyway? (y,N) y
    Creating filesystem with 15132670 4k blocks and 3784704 inodes
    Filesystem UUID: 6053673b-d6b0-420d-84da-0669b71a5211
    Superblock backups stored on blocks:
    32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
    4096000, 7962624, 11239424

    Allocating group tables: done
    Writing inode tables: done
    Writing superblocks and filesystem accounting information: done

  10. Reboot the RUT955 device and refer to Results section

Note: The Writing inode tables section might take a long time depending on the size of your SD card (10+ minutes with 64GB SD).