Changes

|March 1.1.3|April 2017|TBD*Added several packages to the root file system*Removed <code>busybox</code>*Added notes about physical interfaces|-|2.1.0|1.1.3|April 2017|*Added section ''Using the raw image''*Added notes about <code>ssh</code> server configuration*Added notes about <code>MySQL</code> server installation and configuration

Several "distributions" are available for embedded Linux devices. [https://www.yoctoproject.org Yocto] and [https://buildroot.org Buildroot] are just two examples of the most common. Nevertheless, for some applications the use of a desktop/server distribution might be preferable. Since they are not conceived for embedded platforms, these distributions have to be carefully tailored, in order to match hardware resources.[1]

The following box shows how to perform such operations. It is assumed that the microSD card (mapped is connected to the host machine. As such, the two partitions are mounted as <code>/devmedia/BOOT</code> and <code>/media/TBDROOTFS</code> in the example) is connected to a Linux host, . The kernel image and that the partition compressed archive containing the root file system is mounted are available for download at the following URLs respectively:* https://mirror.dave.eu/lynx/debian/20170403/xuelk-1.1.3_uImage.debian* https://mirror.dave.eu/lynx/debian/20170403/20170403-sbclynx-debian-8.tgz To copy the kernel image to the microSD card, issue the following command:<pre class="board-terminal">cp -v xuelk-1.1.3_uImage.debian /media/BOOT/</pre>Delete all the existing files in the <code>/media(dvdk/ROOTFS</code>partition:<pre class="board-terminal">sudo rm -rf /media/ROOTFS/*sudo tar xvzf 20170403-sbclynx-debian-8.tgz -C /media/ROOTFS/ </pre>Decompress the Debian root file system in the same partition:

TBD copiare immagine kernel in FAT dvdk@osboxes:~$ cd /media/dvdk/ROOTFS/dvdk@osboxes:/media/dvdk/ROOTFS$ sudo rm -rf *...dvdk@osboxes:/media/dvdk/ROOTFS$ sudo tar xvzf /media/sf_shared/2017030420170403-debian8sbclynx-nodebian-busybox8.tgz TBDdvdk@osboxes:-C /media/dvdkROOTFS/ROOTFS$ sync

You can now remove Remove the card from the host and plug it into the slot of SBC Lynx.

[1] The only difference with respect to the XUELK kernel image is related to the WiFi driver. To make it work with the Debian root file system, it has to be built as a loadable module instead of as a statically linked driver.

Of course, one of the greatest - if not ''the'' greatest - pros of having a desktop distribution, is the availability of a huge archive of pre-built packages. They can be installed very easily with tools such as [https://wiki.debian.org/Apt <code>apt</code>] and [https://packaging.python.org <code>pip</code>].

Please note the that these changes will take effect after rebooting the machine. 

Please refer to See [[#Adding packages|this section]]. 

<preclass="board-terminal">

<preclass="board-terminal">

The procedure here described can be used to connect to an Access Point, using the WPA2/PSK security protocolwith network address given by the AP via DHCP. User can also follow [https://wiki.debian.org/WiFi/HowToUse#Command_Line this guide from Debian Wiki] for a generic approach.

As the WiFi driver is not statically linked to the kernel image, it is necessary to load the module first. This operation is done automatically upon boot, as the module is listed in <code>/etc/modules</code>:

root@arm:~# modprobe cat /etc/modules# /etc/modules: kernel modules to load at boot time.## This file contains the names of kernel modules that should be loaded# at boot time, one per line. Lines beginning with "#" are ignored. wl12xx

 ThenIn case you need to unload/load the module manually, bring the interface upfollowing commands can be used:

root@arm:~# iw devphy#0 Interface wlan0 ifindex 4 wdev 0x1 addr 88:33:14:5e:30:61 type managedrmmod wl12xxroot@arm:~# ip link show wlan04: wlan0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop qlen 1000 link/ether 88:33:14:5e:30:61 brd ff:ff:ff:ff:ff:ffmodprobe wl12xxroot@arm:~# ip link set wlan0 up[ 2762751.076847040431] wlcore: firmware booted (Rev 6.3.10.0.133)[ 276.097912] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not readyroot@arm:~# ip link show wlan04: wlan0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq qlen 1000 link/ether 88:33:14:5e:30:61 brd ff:ff:ff:ff:ff:ffroot@arm:~# iw wlan0 linkNot connected.loaded

 The connection will be established Once the WiFi module is loaded, it's time to configure the interface: first of all we need to fix interface renaming with the SSID named <code>SSID_ZyXEL_WPA2</code>following command:

root@arm:~# iw wlan0 scan...BSS fe:f0:28:cc:03:90(on wlan0) TSF: 42646261 usec (0d, 00:00:42) freq: 2437 beacon interval: 100 TUs capability: ESS Privacy ShortPreamble ShortSlotTime (0x0431) signal: ln -53.00 dBm last seen: 0 ms ago SSID: SSID_ZyXEL_WPA2 Supported rates: 1.0* 2.0* 5.5* 11.0* 6.0 9.0 12.0 18.0 DS Parameter set: channel 6 RSN: * Version: 1 * Group cipher: TKIP * Pairwise ciphers: TKIP * Authentication suites: PSK * Capabilities: 1s /dev/null /etc/systemd/network/99-PTKSA-RC 1-GTKSA-RC (0x0000) ERP: <no flags> Extended supported rates: 24.0 36.0 48.0 54.0 WMM: * Parameter version 1 * BE: CW 15-1023, AIFSN 3 * BK: CW 15-1023, AIFSN 7 * VI: CW 7-15, AIFSN 2, TXOP 3008 usec * VO: CW 3-7, AIFSN 2, TXOP 1504 usec..default.link

 Add Generate the passphrase key to PSK from the <code>wpa_supplicant</code> configuration file ESSID and make it readable by the clear text passphrase using <code>rootwpa_passphrase</code> onlytool:

root@arm:~# wpa_passphrase SSID_ZyXEL_WPA2 >> /etc/wpa_supplicant.conf# reading passphrase from stdin

Start User can now restart <code>wpa_supplicantsystemd</code>networking service with:

 Once Now you can check the connection process completed successfullysystem configuration using standard tools (<code>route</code>, <code>ifconfig</code>, <code>iw</code> reports ). E.g. to check the WiFi link status as followsuse:

</pre>All of the above configuration are persistent at reboots and automatically started by <code>systemd</code> at boot time. ==Miscellaneous configurations=====<code>ssh</code> server===The configuration file <code>/etc/ssh/sshd_config</code> is set to permit <code>root</code> user to log in.===Installing MySQL server with remote access===This section shows how to install MySQL server and how to enable remote access for <code>root</code> user.{{ImportantMessage|text=From a security standpoint, giving <code>root</code> user logon permission from any host may be dangerous.}}

After assigning a (static) IP address to Firstly, install the <code>wlan0mysql-server</code> interfacepackage. During the installation process, it is possibile to ping you will set the Access Pointpassword for the <code>root</code> user:

root@arm:~# ifconfig wlan0 192sudo apt-get updateGet:1 http://security.debian.org jessie/updates InRelease [63.1 kB]...Reading package lists.168.11.81Doneroot@arm:~# ifconfigsudo apt-get install mysql-serverReading package lists... DoneBuilding dependency treeeth0 Link encap...After this operation, 85.1 MB of additional disk space will be used.Do you want to continue? [Y/n]Get:Ethernet HWaddr 001 http:50:C2:1E:AF:E9 inet addr:192//security.debian.org/ jessie/updates/main mysql-common all 5.1685.54-0.+deb8u1 [81 Bcast:192.1682 kB].0.255 Mask:255.255Configuring mysql-server-5.2555---------------------------- While not mandatory, it is highly recommended that you set a password for theMySQL administrative "root" user.0 inet6 addrIf this field is left blank, the password will not be changed. New password for the MySQL "root" user: fe80   Repeat password for the MySQL "root" user:  Selecting previously unselected package libaio1:250armhf....Processing triggers for systemd (230-7~bpo8+2) ...root@arm:c2ff~#</pre>  Verify the server is up and running:fe1e<pre class="board-terminal">root@arm:afe9/64 Scope~# mysql -u root -pEnter password:Link UP BROADCAST RUNNING MULTICAST Welcome to the MySQL monitor. MTU:1500 Metric:1Commands end with ; or \g.Your MySQL connection id is 43 RX packets:35226 errorsServer version:5.5.54-0 dropped+deb8u1 (Debian) Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or itsaffiliates. Other names may be trademarks of their respectiveowners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql> exitByeroot@arm:0 overruns~#</pre>  Edit the <code>/etc/mysql/my.cnf</code> file in order to comment out the following lines:<pre class="board-terminal">#bind-address = 127.0 frame:.0.1#skip-networking</pre> TX packets Restart the server to make the changes take effect:28 errors<pre class="board-terminal">root@arm:0 dropped~# service mysql restart</pre>  Access MySQL server locally and issue the commands shown below:0 overruns<pre class="board-terminal">root@arm:0 carrier~# mysql -u root -pEnter password:0 collisionsWelcome to the MySQL monitor. Commands end with ; or \g.Your MySQL connection id is 37Server version:5.5.54-0 txqueuelen:1000+deb8u1 (Debian)  RX bytes:3555583 Copyright (3c) 2000, 2016, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or itsaffiliates. Other names may be trademarks of their respectiveowners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql> GRANT ALL PRIVILEGES ON *.3 MiB) TX bytes:1906 * TO 'root'@'%' IDENTIFIED BY 'password' WITH GRANT OPTION;Query OK, 0 rows affected (10.8 KiB01 sec)

lo Link encap:Local Loopbackmysql> SELECT * from information_schema.user_privileges where grantee like "'root'%";+--------------------+---------------+-------------------------+--------------+| GRANTEE | TABLE_CATALOG | PRIVILEGE_TYPE | IS_GRANTABLE |+--------------------+---------------+-------------------------+--------------+| 'root'@'localhost' | def | SELECT | YES || 'root'@'localhost' | def | INSERT | YES || 'root'@'localhost' | def | UPDATE | YES || 'root'@'localhost' | def | DELETE | YES || 'root'@'localhost' | def | CREATE | YES || 'root'@'localhost' | def | DROP | YES || 'root'@'localhost' | def | RELOAD | YES || 'root'@'localhost' | def | SHUTDOWN | YES || 'root'@'localhost' | def | PROCESS | YES || 'root'@'localhost' | def | FILE | YES || 'root'@'localhost' | def | REFERENCES | YES || 'root'@'localhost' | def | INDEX | YES || 'root'@'localhost' | def | ALTER | YES || 'root'@'localhost' | def | SHOW DATABASES | YES || 'root'@'localhost' | def | SUPER | YES || 'root'@'localhost' | def | CREATE TEMPORARY TABLES | YES || 'root'@'localhost' | def | LOCK TABLES | YES || 'root'@'localhost' | def | EXECUTE | YES || 'root'@'localhost' | def | REPLICATION SLAVE | YES || 'root'@'localhost' | def | REPLICATION CLIENT | YES || 'root'@'localhost' | def | CREATE VIEW | YES || 'root'@'localhost' | def | SHOW VIEW | YES || 'root'@'localhost' | def | CREATE ROUTINE | YES || 'root'@'localhost' | def | ALTER ROUTINE | YES || 'root'@'localhost' | def | CREATE USER | YES || 'root'@'localhost' | def | EVENT | YES || 'root'@'localhost' | def | TRIGGER | YES || 'root'@'localhost' | def | CREATE TABLESPACE | YES || 'root'@'arm' | def | SELECT | YES || 'root'@'arm' | def | INSERT | YES || 'root'@'arm' | def | UPDATE | YES || 'root'@'arm' | def | DELETE | YES || 'root'@'arm' | def | CREATE | YES || 'root'@'arm' | def | DROP | YES || 'root'@'arm' | def | RELOAD | YES || 'root'@'arm' | def | SHUTDOWN | YES || 'root'@'arm' | def | PROCESS | YES || 'root'@'arm' | def | FILE | YES || 'root'@'arm' | def | REFERENCES | YES || 'root'@'arm' | def | INDEX | YES || 'root'@'arm' | def | ALTER | YES || 'root'@'arm' | def | SHOW DATABASES | YES || 'root'@'arm' | def | SUPER | YES || 'root'@'arm' | def | CREATE TEMPORARY TABLES | YES || 'root'@'arm' | def | LOCK TABLES | YES || 'root'@'arm' | def | EXECUTE | YES || 'root'@'arm' | def | REPLICATION SLAVE | YES || 'root'@'arm' | def | REPLICATION CLIENT | YES || 'root'@'arm' | def | CREATE VIEW | YES || 'root'@'arm' | def | SHOW VIEW | YES || 'root'@'arm' | def | CREATE ROUTINE | YES || 'root'@'arm' | def | ALTER ROUTINE | YES || 'root'@'arm' | def | CREATE USER | YES || 'root'@'arm' | def | EVENT | YES || 'root'@'arm' | def | TRIGGER | YES || 'root'@'arm' | def | CREATE TABLESPACE | YES || 'root'@'127.0.0.1' | def | SELECT | YES || 'root'@'127.0.0.1' | def | INSERT | YES || 'root'@'127.0.0.1' | def | UPDATE | YES || 'root'@'127.0.0.1' | def | DELETE | YES || 'root'@'127.0.0.1' | def | CREATE | YES || 'root'@'127.0.0.1' | def | DROP | YES || 'root'@'127.0.0.1' | def | RELOAD | YES || 'root'@'127.0.0.1' | def | SHUTDOWN | YES || 'root'@'127.0.0.1' | def | PROCESS | YES || 'root'@'127.0.0.1' | def | FILE | YES || 'root'@'127.0.0.1' | def | REFERENCES | YES || 'root'@'127.0.0.1' | def | INDEX | YES || 'root'@'127.0.0.1' | def | ALTER | YES || 'root'@'127.0.0.1' | def | SHOW DATABASES | YES || 'root'@'127.0.0.1' | def | SUPER | YES || 'root'@'127.0.0.1' | def | CREATE TEMPORARY TABLES | YES || 'root'@'127.0.0.1' | def | LOCK TABLES | YES || 'root'@'127.0.0.1' | def | EXECUTE | YES || 'root'@'127.0.0.1' | def | REPLICATION SLAVE | YES || 'root'@'127.0.0.1' | def | REPLICATION CLIENT | YES || 'root'@'127.0.0.1' | def | CREATE VIEW | YES || 'root'@'127.0.0.1' | def | SHOW VIEW | YES || 'root'@'127.0.0.1' | def | CREATE ROUTINE | YES || 'root'@'127.0.0.1' | def | ALTER ROUTINE | YES || 'root'@'127.0.0.1' | def inet addr:| CREATE USER | YES || 'root'@'127.0.0.1 Mask:255' | def | EVENT | YES || 'root'@'127.0.0.1' | def | TRIGGER | YES || 'root'@'127.0.0.1' | def | CREATE TABLESPACE | YES || 'root'@'::1' | def | SELECT | YES || 'root'@'::1' | def | INSERT | YES || 'root'@'::1' | def | UPDATE | YES || 'root'@'::1' | def | DELETE | YES || 'root'@'::1' | def | CREATE | YES || 'root'@'::1' | def | DROP | YES || 'root'@'::1' | def | RELOAD | YES || 'root'@'::1' | def | SHUTDOWN | YES || 'root'@'::1' | def | PROCESS | YES || 'root'@'::1' | def | FILE | YES || 'root'@'::1' | def inet6 addr| REFERENCES | YES || 'root'@': :1' | def | INDEX | YES || 'root'@'::1/128 Scope' | def | ALTER | YES || 'root'@'::Host1' | def | SHOW DATABASES | YES || 'root'@'::1' | def UP LOOPBACK RUNNING MTU| SUPER | YES || 'root'@':65536 Metric:1' | def | CREATE TEMPORARY TABLES | YES || 'root'@'::1' | def RX packets| LOCK TABLES | YES || 'root'@'::0 errors1' | def | EXECUTE | YES || 'root'@':0 dropped:0 overruns1' | def | REPLICATION SLAVE | YES || 'root'@':0 frame:01' | def | REPLICATION CLIENT | YES || 'root'@'::1' | def TX packets| CREATE VIEW | YES || 'root'@'::0 errors1' | def | SHOW VIEW | YES || 'root'@':0 dropped:0 overruns1' | def | CREATE ROUTINE | YES || 'root'@':0 carrier:01' | def | ALTER ROUTINE | YES || 'root'@'::1' | def collisions| CREATE USER | YES || 'root'@':0 txqueuelen:01' | def | EVENT | YES || 'root'@'::1' | def RX bytes| TRIGGER | YES || 'root'@':0 (0.0 B) TX bytes:0 1' | def | CREATE TABLESPACE | YES || 'root'@'%' | def | SELECT | YES || 'root'@'%' | def | INSERT | YES || 'root'@'%' | def | UPDATE | YES || 'root'@'%' | def | DELETE | YES || 'root'@'%' | def | CREATE | YES || 'root'@'%' | def | DROP | YES || 'root'@'%' | def | RELOAD | YES || 'root'@'%' | def | SHUTDOWN | YES || 'root'@'%' | def | PROCESS | YES || 'root'@'%' | def | FILE | YES || 'root'@'%' | def | REFERENCES | YES || 'root'@'%' | def | INDEX | YES || 'root'@'%' | def | ALTER | YES || 'root'@'%' | def | SHOW DATABASES | YES || 'root'@'%' | def | SUPER | YES || 'root'@'%' | def | CREATE TEMPORARY TABLES | YES || 'root'@'%' | def | LOCK TABLES | YES || 'root'@'%' | def | EXECUTE | YES || 'root'@'%' | def | REPLICATION SLAVE | YES || 'root'@'%' | def | REPLICATION CLIENT | YES || 'root'@'%' | def | CREATE VIEW | YES || 'root'@'%' | def | SHOW VIEW | YES || 'root'@'%' | def | CREATE ROUTINE | YES || 'root'@'%' | def | ALTER ROUTINE | YES || 'root'@'%' | def | CREATE USER | YES || 'root'@'%' | def | EVENT | YES || 'root'@'%' | def | TRIGGER | YES || 'root'@'%' | def | CREATE TABLESPACE | YES |+--------------------+---------------+-------------------------+--------------+140 rows in set (0.0 B02 sec)

wlan0 Link encap:Ethernet HWaddr 88:33:14:5E:30:61mysql> FLUSH PRIVILEGES; inet addr:192.168.11.81 Bcast:192.168.11.255 Mask:255.255.255.Query OK, 0 inet6 addr: fe80::8a33:14ff:fe5e:3061/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:24970 errors:rows affected (0 dropped:0 overruns:0 frame:0 TX packets:12 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:2448625 (2.3 MiB) TX bytes:1291 (1.2 KiB00 sec)

In order You should be able to automatically load the <code>wl12xx</code> module on startup, issue the following commandaccess from remote host:

rootdvdk@armosboxes:~# echo wl12xx >> $ mysql -u root -ppassword -h 192.168.0.81 Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 37 Server version: 5.5.54-0+deb8u1 (Debian) Copyright (c) 2000, 2016, Oracle and/etcor its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/modulesor its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql>