You cannot download Fortinet firmware from random torrent sites. That is a recipe for backdoors and ransomware. You need a legitimate source. Here is the hierarchy of access:
Go to System > Dashboard > Status and click Backup . Fortigate 100d Firmware Download BEST
: Before updating your FortiGate 100D firmware, ensure you have a valid support contract or consult with a Fortinet certified professional. You cannot download Fortinet firmware from random torrent
If your business handles PII (Personally Identifiable Information) or credit card data, you must retire the 100D immediately. Compliance audits (PCI-DSS, HIPAA) explicitly fail EOL firmware. HIPAA) explicitly fail EOL firmware.