{{WarningMessage|text=This application note was validated against specific versions of the kit only. It may not work with other versions. Supported versions are listed in the ''History'' section.}}
== History ==
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An exhaustive discussion of OpenWrt is beyond the scope of this application note. For more information, please refer to [https://openwrt.org the project's home page].
The test bed used for this application note is composed of the same hardware/software platform delivered along with the XUELK. The only relevant difference is related to the root file system, that is . The default one will be replaced with the one generated by the OpenWrt build process, as described in the follwing sections.
==Donwloading, configuring and building==
The following commands can be used to generate a root file system for ARM Cortex-A7 target, such as SBC Lynx.
First of all, download the required file are downloadedfiles:
<pre>
git clone https://github.com/openwrt/openwrt.git
</pre>
Once the build process is completed, the root file system is available in the <code>openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl-1.1.16_eabi/root-brcm2708</code>subdirectory.
==Mounting the OpenWrt file system on the target==
Boot the target using Yocto root file system as root file system, mounted over NFS(192.168.0.80 is the IP address of the NFS server). Once they target has completed the boot process, mount the directory including OpenWrt root file system, and the <code>ext3</code> partition of the microSD card.
<pre>
...
root@sbc-lynx:~# mkdir /mnt/tmp
root@sbc-lynx:~# mkdir /mnt/tmp2
root@sbc-lynx:~# history | grep mount192.168.0.80:/opt/nfsroot/openwrt/root-brcm2708 /mnt/tmp2</pre> Then mount the <code>ext3</code> partition of the microSD card.<pre>
root@sbc-lynx:~# mount -t auto /dev/mmcblk0p2 /mnt/tmp/
</pre>Erase all of the files it cointains.<pre>root@sbc-lynx:~# mount 192.168.0.80:rm -rf /optmnt/nfsroottmp/openwrt/root-brcm2708 *</mntpre>Copy the files of the OpenWrt file systems into the <code>ext4</tmp2code> partition of the microSD card.<pre>
That target can be rebooted with the [[AXEL_ULite_and_SBC_Lynx_Embedded_Linux_Kit_(XUELK)#Target_setup_and_first_boot|default configuration]], in order to mount the root file system from the <code>ext3</code> partition of the microSD card: