firmware download for 30E

Unfortunately we are not allowed to provide firmware to users without a support contract.
Depending on how you formatted it, the backup partition may still be available for you to boot off of. 
See this article (option [B]): https://community.fortinet.com/t5/FortiGate/FortiGate-BIOS-variations-and-firmware-loading-options/ta-p/190977

Hi Ghobashy01
Be aware that FGT30E will be out of support soon. It doesn't support any firmware higher than 6.x. 
If you are using it just to get used to FortiGate commands it is ok, but if you are planning to use/test any feature available on 7.x or higher you won't be able to do. 

Hi,

YOu can try connecting to the console port and refer to this article to upload backup firmware, you will see that option booth with backup firmware then it will upload the firmware. Formatting and loading FortiGate firmware... - Fortinet Community

if not then you can try downloading from your support portal, if you don't have a portal then we won't be able to provide firmware without a support contract.