Downgrade firmware Forti OS 5.0 - Fortigate 100D

[denny8antuno]

Hello, can someone list the steps to downgrade Fortigate 100D with fortiOS v. 5.0X to v.4.0 (for instance MR 3 patch 15)? I read on release note that I have to use TFTP server but I need more detailed informations; need I to format the flash? Thanks in advance. Daniele

[GusTech]

It is described in the v5 documentation, I believe. But, just curious.. Why do you want to downgrade to v4mr3p15 100d???

[Anonymous5]

Hi, Actually I need to perform also this downgrade. Can anybody supply a link to guide? I need to upgrade my 110c(v4) to my 100D(v5), so I need to downgrade the 100D so the configuration fits the version. I tried to change it by the guide but no luck. Thanks in advance.

[rickards]

Just set up an tftp server and reboot the FGT, when it starts again interupt the boot sequence and then you can choose to upload new firmware using tftp.