Changing the Secondary Firmware to Version 18.5 MR3 Build 408

Hello Wilson James Wong,

Thank you for reaching out to the community, please refer the following articles below:
>Move to a different firmware version: https://docs.sophos.com/nsg/sophos-firewall/19.0/Help/en-us/webhelp/onlinehelp/AdministratorHelp/BackupAndFirmware/Firmware/FirmwareMoveToDifferentVersion/index.html

Hi Vivek. Please be informed that I only have 1 XG firewall as of the moment.

Hey Wilson James Wong,

You can upload & boot the next firmware i.e. N+1 But you can not upload and boot Previous firmware i.e. N-1
You can re-image the firmware with **SFOS 18.5.1 MR-1-Build326 & then you can upload the firmware SFOS 18.5.4 MR-4-Build418 in the second slot that why you'll achieve what you want !!
> SFOS Installers: https://download.sophos.com/network/SophosFirewall/installers/index.html

But **Note: SFOS 18.5.1 MR-1-Build326 is declared EoL 30th June'22

Than you for this Vivek. Now waiting for your approval for me to download and receive the .iso file of SFOS 18.5 MR3

Did I understand it correctly? For me to download it you must approve it from your side first?

I do received a reference number from my download request.

Nope, you can straight away download the installers from the provided link !! 
Wilson James Wong

It says. 

Further validation required

Sophos is committed to fully complying with all laws regulating the supply of our products and services. This includes conducting routine checks to ensure we meet required standards for distributing security software and hardware.

You will receive an email from our Export Compliance partner. Please make sure the email address admin@amberroad.com is not blocked.

Your reference:

It generally downloads quickly & almost immediately but if you are having such trouble you may contact customer care team !! 

Now able to download. How to upload this .iso file to overwrite the unsupported firmware SFOS 18.5.1 MR-1-Build326

Thanks in advance. We're almost there Vivek.

Now able to download. How to upload this .iso file to overwrite the unsupported firmware SFOS 18.5.1 MR-1-Build326

Thanks in advance. We're almost there Vivek.

Hey Wilson James Wong,

You'll have to re-image the complete appliance: So ensure you have a back up of  18.5.3 MR-3-Build408
> Guide: https://docs.sophos.com/nsg/sophos-firewall/19.0/Help/en-us/webhelp/onlinehelp/AdministratorHelp/BackupAndFirmware/Firmware/FirmwareReimageXGFirewall/index.html

> Once you have restored the backup then you can go ahead in the back up/firmware option in the empty slot you can upload the  SFOS 18.5.4 MR-4-Build418
> From the following link: https://download.sophos.com/firmware/HW/index.html [pgp up2date file of MR-4]

> You can go ahead and upload & boot the firmware so you'll have SFOS 18.5.4 MR-4-Build418 as the active & 18.5.3 MR-3-Build408 as a backup firmware.
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**Note: You can restore the backup equivalent or higher but not to the lower firmware !! 
eg you can restore the back of v18.5 MR-3 to v18.5.3 or higher but not a back up of v18.5.4 to v18.5.3 !!  

Will follow your instructions and get back to you on this. Thank you so much!