Firmware Update

To update the firmware, Overvis MC251 uses the MC251FW1.FUS, MC251FW2.FUS or MC251FW3.FUS file in the UPGRADES folder on the memory card formatted in FAT or FAT32 format.

• КаталогUPGRADES/

  • MC251FW1.FUS
  • MC251FW2.FUS
  • MC251FW3.FUS

Before you start

Data Safety

• Automatic firmware update does not erase your device configuration or Modbus settings.
• Manual update to a newer version in most cases retains the settings, unless specifically warned so in the firmware description.
• Automation tasks, settings, logs and historical data stored on the SD card are not erased by an update.

Power Supply

Ensure the device has a stable power supply during the update process. Do not power off the device while the update is in progress (usually 2-4 minutes).

Recoverability

The update process faults (e.g. caused by power losses or memory card failure) are recoverable, by repeating the update until it is complete. The update file passes multi-stage check before the update starts. In case of memory card failure and file damage, the update can be completed by replacing the card with the file manually.

Checking current version

Before updating, check your current firmware version to see if an update is necessary. You can find the version number:

• At the bottom of the Web Interface pages, or on the Firmware panel of the Administration tab.
• On the device display during the startup sequence.
• By reading Modbus register 1.

Updating from the file can be done in the firmware update mode.

Getting the update file into MC251

The update files can be written to the MC251 memory card in 4 ways:

1. Automatically via Internet

   MC251 is by default configured to periodically check the updates server and download the newer firmware, when Internet connection is available.

   Note: Ensure your device has a valid Internet Gateway and DNS server configured in the Ethernet settings, or has a GSM/LTE Internet access.

2. Using WEB interface

   1. Access the device using the browser (see Web Interface);
   2. If the newer firmware is available on the server, and the download has not started automatically, the Download Update button will appear at the bottom of the the page;
   3. Press the Download Update button to start the download process;
   4. The download progress will be displayed on the page;
   5. After the download completion, the file will be checked. This may take a minute;
   6. After the file check, the update prompt with Install Update button will be displayed, confirming that the file suits.

3. Using Modbus commands

   • Connect to the device via Modbus and enter the setup mode (see Configuration via Modbus);
   • To verify the version of the downloaded update file, read the header line in registers 2030 - 2061 (ASCII string);
   • To download the newer version from the cloud server, write the value 64893 into the control command register 120;
   • Control file download by reading registers 2004 - 2005;
   • After download completion, double-check the version of the downloaded file.

4. Write files to SD card

   Download the latest firmware from the Firmware Downloads page.

   1. Ensure the SD card is formatted in FAT or FAT32.
   2. Create a folder named UPGRADES in the root of the card.
   3. Rename the downloaded firmware file to one of the following names (must be uppercase):
      • MC251FW1.FUS
      • MC251FW2.FUS
      • MC251FW3.FUS
   4. Copy the file into the UPGRADES folder.
   5. Insert the card into the MC251 (see below for instructions on updating from a file).

Updating MC251 from the file

MC251 firmware can be updated from the file on the memory card in 4 ways:

1. Automatically

   MC251 is by default configured to start update from the newer firmware file at a night hour (default is 03:00 AM).

2. Using WEB interface

   1. Access the device using the browser (see Web Interface);
   2. If the newer firmware file is available on the memory card, the Install Update button will appear at the bottom of the page;
   3. Press the Install Update button to start the firmware update process.

3. Using Modbus commands

   • Connect to the device via Modbus and enter the setup mode (see Configuration via Modbus);
   • To verify the version of the downloaded update file, read the header line in registers 2030 - 2061 (ASCII string);
   • If the required file is loaded, write the value 65397 into the control command register 120 to start the update.

4. Manually

   By entering the firmware update mode and selecting the firmware update (see below).

At the update command the device will automatically restart and enter update mode. Wait for the firmware update, the process may take 2 to 4 minutes.

Firmware update mode

MC251 can be put into firmware update mode during device power up or restart.

The firmware update mode may be entered automatically (e.g. by a web-interface command or in case of updating failure) or manually (or if the button R has been pressed during startup. The R button is the recessed button located on the front panel of the device).

Table 1 - Manually entering the firmware update mode

No.	Step	R button	Display	Time	Remark
1	Initialization	Pressed		1.5 s	To cancel entering the update mode, release R button
2	Notification about entering the update mode	Pressed	Entering upgrade mode	5 s	To cancel entering the update mode, release R button
3	Offer to enter the update mode	Pressed	To enter upgrade mode release button	2 s	Release the button at this step in order to enter the update mode
4	Protection against incidental pressing	Pressed			Holding the button pressed will cancel entering the update mode

After entering this mode manually, the update file has to be selected. To cancel the updating, cut off the power supply of MC251 or wait until the update mode is exited automatically due to file selection absence.

Table 2 – Update file selection

No.	Step	R button	Display	Time	Remark
1	Finding the available files		Searching for upgrade files…	(depends on the files found)
2	Offering of the update file	Released	(name and version of the update file)	5 s	To select a file, press and release R button at this step
3	Offering all the update files	Released		(depends on the found files)	Step 2 is repeated for each update file
4	Repeating the offer	Released		(depends on time of step 3)	Steps 2 - 3 are repeated 3 times
5	Protection against unintentional update mode entrance	Released			The absence of selection causes the update mode exit

At automatic update mode entrance (or after the manual selection of the file), the firmware update is started.

Table 3 – Firmware update

No.	Step	R button	Display	Time	Remark
1	Update start		Firmware upgrade	2 – 10 s
2	Update process		(progress bar shows the process of updating)	(depends on the update file)
3	Updating is successfully completed		Firmware upgrade success	3 s
4	Startup of the firmware

The errors and warnings during the updating process are shown on the display.

ATTENTION

IN CASE OF A CRITICAL ERROR DURING THE UPDATE, THE OPERATION OF THE MC251 DEVICE IS NOT POSSIBLE. REPLACEMENT OF MEMORY CARD AND/OR FILE AND MANUAL UPDATE PROCESS REPEAT ARE REQUIRED TO RECOVER THE DEVICE. IN CASE THE PROBLEM REPEATS, PLEASE CONTACT THE MANUFACTURER.

If the critical error is met, the indication of a critical error is made during an hour, after that the MC251 device automatically restarts. If an error is a result of an incidental event, the firmware will be restored from the file on the memory card.

Table 4 – Firmware update mode warning and error codes

Code	Warning	Automatic actions	Remark
2	Firmware cannot be started	Initialization of emergency update mode: autostart updating from the selected file or from the first available file (if any)	The warning is a result of other errors and is automatically corrected using the available update files
3	Error during the firmware update process	Similar to No.2, but the file with an error has less priority.	The error is automatically corrected using the available update files
4	The update files are not available	Escape from the update mode and start the available firmware	MC251 can continue operation, but the update file should be put into the UPGRADES folder on the memory card in order to update firmware
5	Emergency - firmware cannot be started	Waiting for manual restart of the device or restart automatically in 1 hour	The error is met after a triple emergency mode entrance as a result of other errors. The correct firmware update file should be put into the UPGRADES folder on the memory card. If the error is repeated, contact the manufacturer
6	Emergency - error during the firmware update process	Waiting for manual restart of the device or restart automatically in 1 hour	The error is met after a triple emergency mode entrance as a result of other errors. The correct firmware update file should be put into the UPGRADES folder on the memory card. If the error is repeated, contact the manufacturer
7	Emergency - no available update files, and the firmware cannot be started	Waiting for manual restart of the device or restart automatically in 1 hour	The error is met after a triple emergency mode entrance as a result of other errors. The correct firmware update file should be put into the UPGRADES folder on the memory card. If the error is repeated, contact the manufacturer

Troubleshooting & FAQ

Q: Will I lose my configuration or data during an update?

A: No, the firmware update to a newer version process is designed to preserve your device configuration, Modbus settings, and historical data. However, downgrading the firmware may revert the settings to factory defaults. In either case, backing up critical data is always recommended.

Q: The “Download Update” button is not appearing in the Web Interface.

A: This can happen if:

• The device is already running the latest firmware.
• The device does not have Internet access. Check your Gateway and DNS settings.
• The update server is temporarily unreachable.
• The memory card is absent/full/faulty.

Q: The firmware does not update automatically.

A: This can happen if:

• The device is already running the latest firmware.
• The device does not have Internet access. Check your Gateway and DNS settings.
• The update server is temporarily unreachable.
• The memory card is absent/full/faulty.
• The device is not powered on at an update hour (at nighttime by default)

Q: The device does not see the manually written file on the memory card.

A: The file should be named MC251FW2.FUS and placed into the UPGRADES folder on the FAT32 microSD memory card. Check also the following:

• The file is the correct MC251 update file downloaded from the Firmware Downloads.
• The memory card is inserted.

Q: The update process seems to hang.

A: The update process typically takes 2-4 minutes. If it takes significantly longer:

• Do not power off the device immediately.
• Check the device display for any error codes (see Table 4).
• If the device is unresponsive for over 10 minutes, try a manual restart. If the internal firmware is corrupted, the device should enter the emergency update mode from the file automatically.

Q: Can I downgrade the firmware?

A: Yes, you can install an older firmware version by manually placing the older firmware file (renamed to MC251FW1.FUS) in the UPGRADES folder on the SD card and initiating the update. However, the device settings are not always retained and may be reverted to factory defaults after firmware upgrade.

Need Help?

For technical support and assistance:

• Email: support@overvis.com
• Support portal: www.overvis.com/support