UISP Fiber - How to Recover the UFiber OLT

In rare cases when an OLT becomes unresponsive, these instructions may be suggested by our support team to recover the OLT back to its default state. This is typically not the first step in troubleshooting issues, but rather a last resort recovery method. This process will completely restore the device to the factory default settings and erases all custom configuration. 

The recovery image can be found on the UFiber Downloads page and is different than the OLT update firmware.

Connecting to Serial Console

The default serial port settings are listed below:

  • Baud rate 57600
  • Data bits 8
  • Parity NONE
  • Stop bits 1
  • Flow control NONE 

In order to connect to the console we will need to use the following items/programs:

  • USB to DB9 adapter
  • Terminal emulation program, such as PuTTY or the macOS/Linux terminal

1. Open the terminal emulator and specify the serial COM line and the baud rate/speed.

Windows Client

Enter the following information in the PuTTY window.


macOS Client

Open Terminal Application and find the serial interface ID.

ls -ltr /dev/*usb*

The serial interface will display as tty. Example output below:

ls -ltr /dev/*usb*
crw-rw-rw-  1 root  wheel   21,   3 Feb  8 15:48 /dev/cu.usbserial-AI038TPF
crw-rw-rw-  1 root  wheel   21,   2 Feb  9 08:56 /dev/tty.usbserial-AI038TPF

Use the screen command to connect to console by pasting in the path to the serial interface.

screen /dev/tty.usbserial-AI038TPF 57600

Note: Replace/dev/tty.usbserial-AI038TPF with the specific value unique to your environment when using the ls -ltr /dev/*usb* command.

2. Connect to the OLT management port with a separate Ethernet cable.

3. Assign a static IP address to your computer's network interface, for example

4. Leave the console window open and both cables plugged in while continuing on to the next section.

Setting up a TFTP Server

The next step is to set up a TFTP server on the computer to allow the recovery image to be uploaded to the OLT.

1. Download the latest OLT recovery file from the UFiber Downloads page.

2. Install a TFTP server. 

Windows Client

In this example we are using Tftpd32 as the TFTP server.

macOS Client

Open a new terminal window to load and start the TFTP service.

sudo launchctl load -F /System/Library/LaunchDaemons/tftp.plist 
sudo launchctl start com.apple.tftpd

Change the file permissions for the TFTP folder.

sudo chmod 777 /private/tftpboot
sudo chmod 777 /private/tftpboot/*

3. Move the OLT recovery file in the base TFTP directory.

Starting the Recovery Process

CLI: Access the UFiber OLT Command Line using the console connection.

1. Connect the power cable to the OLT and boot up the device.

2. Hold down the 1 (number one) key as the OLT starts up to interrupt the boot process.

3. When holding the 1 key, the bootloader will be interrupted and bring you to a prompt similar to the one below.

Please choose the operation: 
1: Load system code to SDRAM via TFTP.
2: Load system code then write to Flash via TFTP.
3: Boot system code via Flash (default).
4: Entr boot command line interface.
7: Load Boot Loader code then write to Flash via Serial.
9: Load Boot Loader code then write to Flash via TFTP.
default: 3

4. Select option 1 and enter the required IP address and filename recovery information.

  • Device IP This is the IP address to assign to the OLT.
  • Server IP This is the IP address of the TFTP server (computer).
  • Linux Kernel Filename Exact name of the OLT recovery image in the base TFTP directory.

An example output is:

1: System Load Linux to SDRAM via TFTP. 
Please Input new ones /or Ctrl-C to discard
Input device IP ( ==:
Input server IP ( ==:
Input Linux Kernel filename (vme600) ==:OLT.recovery.v4.1.0.2648.191120.1333.16de5fdde.img

After completing the steps above, the # symbol will be shown many times as the file is uploaded to the device. This is the expected behavior.

The OLT will reboot automatically after the recovery process completes. During the process the fans may run at full speed.

A successful recovery will allow management access via the web UI or CLI using the DHCP assigned IP address or the fallback address ( on the management port.

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