Backup the Running Configuration File

Before the upgrade, user can back up the configuration file prior to upgrading the switch.
If user is running L2/L3 mode, the configuration file is /pica/config/pica_startup.boot
If user is running OVS mode, the configuration files are located in /ovs/ovs-vswitchd.conf.db.

Download the PicOS 2.3 Image

Download the PicOS 2.3 image for P-3922 from the Pica8 website. Visit http://www.pica8.com/portal/ to register for a Pica8 Portal account. Once the registration is approved, login and download the images from the portal. Save the downloaded image at a local TFTP or FTP server.

Prepare the USB NAND

The boot loader, uBoot, provides the different boot commands to enter either the flash Linux environment or the PicOS system on the CF card. By default, it brings up PicOS. uBoot provides two commands to boot into different environments. One is to the PicOS system and the other to the backup Linux. By default, uBoot boots into PicOS on the first partition. To upgrade to the latest PicOS 2.3, manually bring up backup Linux by stopping uBoot.
Press Ctrl+C and the Ctrl+U after user sees the display below,

Starting Power-On Self Test ..。

This will boot into the backup Linux. When seeing the password prompt, enter mercury, then hit enter:

Password : *******

Hit any key when the display below is shown,

Hit any key to stop autoboot: 5

Next, enter the following command to boot up backup Linux:

=>run usb_backup_boot

Press any key to enter the shell when the display below is shown:

sd 0:0:0:0: [sda] Assuming drive cache: write through
sd 0:0:0:0: [sda] Assuming drive cache: write through
sda: sda1 sda2 sd 0:0:0:0: [sda] Assuming drive cache: write through
sd 0:0:0:0: [sda] Attached SCSI disk

Mounting the USB NAND Flash and Saving the Running Configuration File

Enter the following command to mount the first partition on the /mnt directory:

#mount /dev/sda1 /mnt

The current configuration file can be saved before upgrading the image. The configuration files are located in /mnt/pica/config/pica.conf. 

To repartition the USB NAND flash, enter the following command:

#fdisk /dev/sda

Cleaning the USB NAND Flash

To repartition the USB NAND flash, enter the following command:

#fdisk /dev/sda

The old partition can then be removed with the d command

Command (m for help): d
Selected partition 1

A new partition can be created with the n command. Save the information before quitting the fdisk tool.
The following command can build the ext3/ext2 file system over the created partition:

#mke2fs -j /dev/sda1

Finally, mount the first partition:

#mount /dev/sda1 /mnt/

Setting up an IP Address

There are two ways to set up the IP address of the management port:
1. Obtain the IP address through DHCP, or
2. Set up a static IP address.
If the switch is connected to a DHCP server, enter the following command to obtain the DHCP-assigned IP:

#udhcpc

If a DHCP server is not available, set up a static IP instead:

#ifconfig eth0 <IP address>

Check that the switch can ping the server the image is on.

Downloading and Installing the PicOS Image

If you did not perform the steps to cleaning and re-formating the old USB NAND Flash, please remove the old PicOS before installing the new PicOS. Enter the commands as shown below:

# mount /dev/sda1 /mnt/
# rm -rf /mnt/*

Install the new image to partition 1 of the USB NAND Flash. Up to this step, we have mounted partition 1 (/dev/sda1) to /mnt directory.

#cd /mnt

Use TFTP or FTP to retrieve the image from a remote server. When using TFTP, enter rootfs.tar.gz for<local-image-name>. The file name of the new image, which should be stored at the TFTP server, will be needed. Use the file name as <remote-image-name>.
<TFTP-server-IP> is the IP address of the TFTP server. The process may take several minutes. 

# tftp -g -l <local-image-name> -r <remote-image-name> <TFTP-server-IP>
# sync

Or retrieve the image through ftp:

# ftpget -u <user-name> -p <password> <FTP-server-IP> <local-image-name> <remote-image-name>
# sync

Next, un-tar the image:

# tar zxvf rootfs.tar.gz ...
# sync

Do not forget to enter sync command before restarting the system to ensure that the data is written back on the SD card.

Finally, reboot the system:

#sync
#reboot

Please refer to section "Upgrade PicOS from 2.0 to 2.x" for instructions for upgrading to 2.x version.