Guidance on Using SD Card and File Sharing on GL-AR750

Technical Support for Routers VPN, DNS, Leaks
1

I recently upgraded my GL-AR750 to firmware version 4.3.18. After the upgrade, I noticed that the file-sharing feature is missing, and I’ve been struggling to reinstall it through the plug-in system.

My primary goal is to enable the SD card slot on the GL-AR750 for file sharing. Could anyone guide me on:

  1. Which packages are safe to remove to free up space without affecting the router's core functionalities?
  2. The correct steps to install and enable the file-sharing feature so that I can use the SD card slot effectively?

I’d appreciate any detailed instructions or tips from those who’ve encountered and resolved a similar issue.

Thank you in advance for your help!

2

Removing will not save up space. They won't get deleted, just unlinked. You can't save space by removing default firmware files.

3

Hi @admon ,

Thank you for the response. However, I’m encountering issues due to limited space while attempting to install the necessary packages.

I’m a bit confused about the space constraints:

  1. Should I base the available space on memory (RAM) or storage?
  2. I noticed the memory usage increased after the firmware upgrade, but unfortunately, I didn’t capture the usage before the update.

If I decide to revert back to the previous state:

  • Is there a specific procedure to revert changes, or would I need to reset the router to factory defaults again?

Your guidance would be much appreciated. Thank you!

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4

Storage is the important part. If you encounter issues while installing, you need to expand the root-filesystem first by using extroot and an SD card or USB-stick: [OpenWrt Wiki] Extroot configuration

Resetting is the fastest and best way for reverting.

6

Expanding Root Filesystem on GL-AR750 Using a 2GB SD Card

This guide explains how to expand the root filesystem of the GL-AR750 router by setting up extroot with a 2GB SD card (formatted as ext4). Additionally, it covers how to integrate USB storage, which is automatically detected.

Prerequisites

  1. Router: GL-AR750 with the latest firmware.
  2. SD Card: A 2GB SD card (formatted as ext4).
    • Format the SD card using tools like MiniTool Partition Wizard.
  3. USB Drive: Optionally, a USB storage device to verify auto-detection.
  4. SSH Access: Ensure you can SSH into the router.

Procedure

Step 1: Initial Verification

  1. SSH into the router.
  2. Check the current filesystem status:
    df -h
    Expected Output (Before Expansion):
    Filesystem                Size      Used Available Use% Mounted on
/dev/root                11.8M     11.8M         0 100% /rom
tmpfs                    59.2M    496.0K     58.7M   1% /tmp
tmpfs                    59.2M    300.0K     58.9M   0% /tmp/root
tmpfs                   512.0K         0    512.0K   0% /dev
/dev/mtdblock6            1.4M    296.0K      1.1M  20% /overlay
overlayfs:/overlay        1.4M    296.0K      1.1M  20% /

Step 2: Prepare the SD Card

  1. Insert the 2GB SD card into the router.

  2. Verify that the SD card is detected:

    ls /dev

    Look for /dev/sda1 (or similar).

  3. Temporarily mount the SD card to verify functionality:

    mkdir -p /mnt/sd
mount /dev/sda1 /mnt/sd
df -h

    You should see the SD card listed:

    /dev/sda1                 1.7G      2.0K      1.6G   0% /mnt/sd

Step 3: Configure Extroot

  1. Copy the router's current overlay data to the SD card:

    cp -a /overlay/* /mnt/sd/

    This ensures all configurations are preserved.

  2. Edit the fstab configuration to use the SD card as the overlay:

    vi /etc/config/fstab

  3. Add or update the following entries:

    config 'global'
    option  anon_swap       '0'
    option  anon_mount      '0'
    option  auto_swap       '1'
    option  auto_mount      '1'
    option  delay_root      '5'
    option  check_fs        '0'

config 'mount'
    option  target  '/overlay'
    option  device  '/dev/sda1'
    option  fstype  'ext4'
    option  options 'rw,sync'
    option  enabled '1'

Step 4: Apply Changes and Reboot

  1. Unmount the SD card from its temporary mount:
    umount /mnt/sd
  2. Reboot the router to activate the extroot configuration:
    reboot

Step 5: Verify Expanded Filesystem

  1. SSH into the router again after rebooting.
  2. Run df -h to verify the filesystem:
    Expected Output (After Expansion):
    Filesystem                Size      Used Available Use% Mounted on
/dev/root                11.8M     11.8M         0 100% /rom
tmpfs                    59.2M      2.7M     56.4M   5% /tmp
overlayfs:/overlay        1.7G     35.7M      1.6G   2% /
tmpfs                   512.0K         0    512.0K   0% /dev

Step 6: Add USB Storage (Optional)

  1. Install necessary packages to support USB storage:
    opkg update
opkg install gl-sdk4-nas-utils gl-sdk4-nas-web samba4-server kmod-fs-ext4 kmod-fs-ntfs
  2. Plug in the USB drive.
  3. The USB storage will be automatically detected and mounted by the router's system.
  4. Run df -h to verify:
    Expected Output (With USB and SD Card):
    Filesystem                Size      Used Available Use% Mounted on
/dev/root                11.8M     11.8M         0 100% /rom
tmpfs                    59.2M      2.7M     56.4M   5% /tmp
overlayfs:/overlay        1.7G     35.7M      1.6G   2% /
tmpfs                   512.0K         0    512.0K   0% /dev
/dev/sdb1                15.0G    680.0K     15.0G   0% /tmp/mountd/disk1_part1
/dev/sda1                 1.7G     35.7M      1.6G   2% /tmp/mountd/disk2_part1

Notes

  1. Factory Reset Behavior
    If the router is reset to factory defaults, the extroot configuration will be erased. You will need to reconfigure the overlay if necessary.

  2. Troubleshooting

    • If the SD card is not detected, ensure it is formatted as ext4.
    • If the router fails to reboot properly, check the /etc/config/fstab file for syntax errors.