UFiber GPON - How to Recover the UFiber OLT


In this article we will provide the necessary steps to recover the UFiber OLT. This process will completely restore the UF-OLT to factory default settings and erase all custom configuration.

The recovery image is different than the OLT update firmware. The recovery images can be found on the UFiber download page.
Devices used in this article:

Table of Contents

  1. Introduction
  2. Connecting to the Console and Management Port
  3. Set up a TFTP Server
  4. Start the Recovery Process
  5. Related Articles


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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.

Connecting to the Console and Management Port

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The first step is to connect to the console and management ports of the UF-OLT. 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 you will need to use the following items/programs:

  • RJ45 to DB9 serial console cable (rollover cable)
  • USB to DB9 adapter
  • Terminal emulation program, such as PuTTY or the macOS/Linux terminal


1. Using a USB to serial cable, connect to the OLT console port.

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

2.1 For Windows:



2.2 For macOS/Linux:


Open Terminal Application in macOS and find the serial interface ID:

ls -ltr /dev/*usb*

The serial interface will show ".tty"  here is an example:

mac:~ admin$ 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 screen command to connect to console by pasting in the path to the serial interface.

screen /dev/tty.usbserial-AI038TPF 57600
ATTENTION: Each serial interface will be unique, do not copy the command above exactly. Replace /dev/tty.usbserial-AI038TPF with the value given when using the ls -ltr /dev/*usb* command.

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

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

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

Set up a TFTP Server

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The next step is to set up a TFTP server on the workstation to allow the UFiber OLT to boot from TFTP.

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

2. Install a TFTP server.

2.1 For Windows:


Download and install Tftpd32 or Tftpd64 and place the OLT recovery file in the base TFTP directory.

2.2 For macOS/Linux:


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

Set the file permissions for the TFTP folder:

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

Place the OLT recovery file in the base TFTP directory.

Start the Recovery Process

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CLI: Log into the UFiber OLT from the console connection using your credentials. 

1. Reboot the UFiber OLT from the console window by running the following command:


2. Hold down the 1 (number one) key as the OLT reboots.

3. When holding the 1 key, the bootloader will be interrupted and bring you to a prompt like 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 IPThis is the IP address that the OLT should use for the TFTP session.
  • Server IPThis is the IP address of the TFTP server (computer).
  • Linux Kernel FilenameExact 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.

After entering the recovery image file name and pressing the enter key, the OLT will scroll though showing the # symbol many times as it it loads the file to the OLT. This is expected behavior.

Next the OLT will the remove and re-install the image, then reboot. As this occurs, you will also notice the fans speed may run at full speed until the process completes.

5. A successful recovery will allow management access by logging in via the console, web UI or SSH on the default IP address.

Related Articles

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UFiber GPON - Getting Started

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