TP-Link MR3020 ExtRoot and 3G Modem (OpenWrt)

This post I expect OpenWrt has been installed, if not please refer my previous post. The full documentation about Extroot can be found from this link http://wiki.openwrt.org/doc/howto/extroot .

The step showed here is the working implementation on TP-Link MR3020 using the following environment.

Firmware Version: OpenWrt Attitude Adjustment 12.09

1. USB 2.0 Hub
2. USB 2.0 Flash Drive (~8GB)
3. ZTE MF-190 3G Modem

The first step you need to format the flash drive to ext4 partition, I use 3rd party software to do this (in Windows 7) which was free MiniTool Partition Wizard Home Edition.

The partition should looks like the screenshot.

I created 1024MB for Swap and the rest for ext4 partition, adjust according to your need just make sure the arrangement ext4 first then the swap. Also ensure create as must be primary. Don’t forget to click apply. The process could take few minutes depends on the size of the disk.

After the partitioning finished plug the flash drive to the router.
Login to the router via SSH, install all the required packages. The router need to have internet to do this.

# opkg update
# opkg install block-mount kmod-usb-storage kmod-fs-ext4

1 2	# opkg update # opkg install block-mount kmod-usb-storage kmod-fs-ext4

Copy the rootfs from flash memory to flash drive that mounted on /mnt/sda1

# mkdir /mnt/sda1
# mount /dev/sda1 /mnt/sda1
# mkdir -p /tmp/cproot
# mount --bind / /tmp/cproot
# tar -C /tmp/cproot -cvf - . | tar -C /mnt/sda1 -xf -
# umount /tmp/cproot

# mkdir /mnt/sda1

# mount /dev/sda1 /mnt/sda1

# mkdir -p /tmp/cproot

# mount --bind / /tmp/cproot

# tar -C /tmp/cproot -cvf - . | tar -C /mnt/sda1 -xf -

# umount /tmp/cproot

I was using pivot overlay for the implementation which mean the /dev/sda1 is mounted to /overlay filesystem.

Edit /etc/config/fstab using your favorite editor.

vim /etc/config/fstab

1	vim /etc/config/fstab

My original configuration.

config global automount
        option from_fstab 1
        option anon_mount 1

config global autoswap
        option from_fstab 1
        option anon_swap 0

config mount
        option target   /home
        option device   /dev/sda1
        option fstype   ext4
        option options  rw,sync
        option enabled  0
        option enabled_fsck 0

config swap
        option device   /dev/sda2
        option enabled  0

config global automount

option from_fstab 1

option anon_mount 1

config global autoswap

option from_fstab 1

option anon_swap 0

config mount

option target /home

option device /dev/sda1

option fstype ext4

option options rw,sync

option enabled 0

option enabled_fsck 0

config swap

option device /dev/sda2

option enabled 0

Change it according to the following

config global 'automount'
        option from_fstab '1'
        option anon_mount '1'

config global 'autoswap'
        option from_fstab '1'
        option anon_swap '0'

config mount
        option target '/overlay'
        option device '/dev/sda1'
        option fstype 'ext4'
        option options 'rw,sync'
        option enabled_fsck '0'
        option enabled '1'

config swap
        option device '/dev/sda2'
        option enabled '1'