104 lines
2.4 KiB
Plaintext
104 lines
2.4 KiB
Plaintext
OpenWrt 24.x Extroot on XE300
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Goal: Use a microSD card as the router's writable storage (overlay),
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single ext4 partition, no data copied from internal flash.
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Device: GL-iNet XE300, OpenWRT 24.10.4, 512 Gb SD Card
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Detected as: /dev/sda with one partition /dev/sda1
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1. Insert card & install required packages
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opkg update
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opkg install block-mount kmod-fs-ext4 kmod-usb-storage e2fsprogs
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block-mount - block info, fstab handling, extroot logic
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kmod-fs-ext4 - kernel driver for ext4 filesystem
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kmod-usb-storage - makes the SD slot show up as /dev/sda
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e2fsprogs - provides mkfs.ext4
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2. Confirm the SD card is /dev/sda and /dev/sda1
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Check dmesg:
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dmesg | grep -i sd
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Sample Output:
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sd 0:0:0:0: [sda] 1000005632 512-byte logical blocks: (512 GB/477 GiB)
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sda: sda1
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sd 0:0:0:0: [sda] Attached SCSI removable disk
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3. Format /dev/sda1 as ext4 for extroot
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mkfs.ext4 -L extroot /dev/sda1
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You should see output ending with success and a UUID.
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4. Grab the UUID and create the extroot fstab entry
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UUID=$(block info | awk -F\" '/sda1/ {print $2}')
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echo $UUID
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Sample UUID output:
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4851f00e-696b-47d3-a529-82c2aca292db
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Now write the minimal extroot config using uci:
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uci set fstab.extroot="mount"
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uci set fstab.extroot.uuid="$UUID"
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uci set fstab.extroot.target="/overlay"
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uci set fstab.extroot.fstype="ext4"
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uci set fstab.extroot.enabled="1"
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uci commit fstab
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Sanity-check the file:
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cat /etc/config/fstab
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Sample output:
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config global
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option anon_swap '0'
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option anon_mount '0'
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option auto_swap '1'
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option auto_mount '1'
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option delay_root '5'
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option check_fs '0'
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config mount 'extroot'
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option uuid '4851f00e-696b-47d3-a529-82c2aca292db'
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option target '/overlay'
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option fstype 'ext4'
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option enabled '1'
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5. Reboot into extroot
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reboot
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Wait for the router to come back up, then SSH in again.
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6. Verify that the SD card is now your root overlay
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df -h
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Expected output:
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Filesystem Size Used Available Use% Mounted on
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/dev/root 4.0M 4.0M 0 100% /rom
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tmpfs 58.7M 200.0K 58.5M 0% /tmp
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/dev/sda1 468.3G 2.1M 444.4G 0% /overlay
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overlayfs:/overlay 468.3G 2.1M 444.4G 0% /
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Explanation:
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/dev/root at /rom → read-only squashfs from flash
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/dev/sda1 at /overlay → SD card is the writable layer
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overlayfs:/overlay on / → full rootfs = ROM + SD overlay
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You now have a 468 GB OpenWrt box.
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No /rwm mount
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No copy of internal overlay
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This is a clean, SD-only overlay setup. |