Log on Without Password

To log onto the target through the serial interface, log on as root with no password. This allows manual changes to other interfaces (e.g., USB if you want to run CDC-ECM).

Use nfs root

The file meta-swi/meta-swi-mdm9x15/conf/machine/qcom-mdm9615.conf contains examples if you need to include a lot of extra packages in your rootfs or if you build the debug version. See README.bsp for details. Remember to untar the generated rootfs to an exported file system. The file pointed to by the rootfs link contains the most recent root file system. There’s more info available at https://www.kernel.org/doc/Documentation/filesystems/nfs/nfsroot.txt.

CDC-ECM for IP vs Ethernet

Using CDC-ECM for IP connections will cause the MAC address to change every reboot because the kernel allocates software-defined MAC addresses to interfaces. This may cause new connections to be detected by your host every time you reboot the device.

Setup Preferred IP

Either boot with an Ethernet cable plugged in and let the device obtain an IP address using DHCP, or enable CDC-ECM and the micro-USB cable. You can then determine the IP address using ifconfig on the console or provide a fixed IP from your DHCP server. Then use ssh and scp to access the device and transfer files. Remember root has no password.

Setup Target Static IP

Configure your target and development PC so it doesn't prompt for a password, run: bin/configtargetssh

It'll look like this:

dave@devbox:~/legato$ bin/configtargetssh 192.168.1.2
Generating new key pair... --->>> LEAVE THE PASSPHRASE EMPTY <<<---
Generating public/private rsa key pair.
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/dave/.ssh/id_rsa.legatoTarget.
Your public key has been saved in /home/dave/.ssh/id_rsa.legatoTarget.pub.
The key fingerprint is:
af:c5:e4:8c:7d:53:b4:a4:72:c8:67:f3:88:9c:3f:67 dave's key for Legato 
target devices.
The key's randomart image is:
+--[ RSA 2048]----+
|                 |
|                 |
|              o  |
|         . . + . |
|        S = * o  |
|         X B =   |
|        . @ + .  |
|         o o..E  |
|        .   .+   |
+-----------------+
/home/dave/.ssh/known_hosts updated.
Original contents retained as /home/dave/.ssh/known_hosts.old
Connecting to the target...  (ENTER TARGET'S ROOT PASSWORD WHENEVER 
PROMPTED FOR A PASSWORD)
(press ENTER if your target doesn't have a root password)
The authenticity of host '192.168.1.2 (192.168.1.2)' can't be established.
RSA key fingerprint is f2:2f:66:a5:14:20:bd:46:8f:a2:02:b3:99:6f:72:24.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.1.2' (RSA) to the list of known hosts.
root@192.168.1.2's password:
dave@devpc:~/legato$

Setup using BSPTestReport.xls

This spreadsheet is used for instructions and reports to help set up different BSP features to test. Start with the Contents sheet.

Read/Write rootfs

It's convenient right now to enable r/w to rootfs, but it will be moving to a read-only model soon. If you change the rootfs (e.g., in /etc, /lib, /bin), you may cripple your device and have to re-install your rootfs.

Disable New Package Download

The Yocto build defaults to disable new package downloads.

Enable downloading new packages over the Internet, modify:

<build-dir>/conf/local.conf value BB_NO_NETWORK to "0" . The file is only present after a build has run once.

Change Default USB Classes

During the boot sequence, startup scripts run the file /etc/legato/usbsetup that enumerates the USB types listed in /etc/legato/usbmode.

Override default types by creating your own usbmode file in /mnt/flash/startup/usb. The new file will take precedence over the old one. By default, the device will enumerate an ECM port, an ACM port for AT commands and USB audio.