FortiGate Next Generation Firewall utilizes purpose-built security processors and threat intelligence security services from FortiGuard labs to deliver top-rated protection and high performance, including encrypted traffic.
Article Id 192483
This article describes different firmware builds available on Fortinet support portal for FortiGate-30E/FortiWifi-30E models.

In order to upgrade the firmware on FortiGate-30E/FortiWifi-30E models, there are several options available on the Fortinet Support portal website.
FortiGate-30E is a special unit available in several hardware configurations; FortiGate (no wireless modules at all), FortiWifi (wireless a/b/g/n).
Each of these models also have 3G/4G variants.

- FGT_30E_MG-v6-buildxxxx-FORTINET.out – Global build – supports units that are capable of using frequencies used by carriers all over the world. Serial number starts with: FGT30EG
- FGT_30E_MN-v6-buildxxxx-FORTINET.out – North American build – supports frequencies used by carriers in North America only. Serial number starts with: FGT30EN
- FGT_30E_MI-v6-buildxxxx-FORTINET.out – International build – supports frequencies used by carriers everywhere but North America. Serial number starts with: FGT30EI
- FGT_30E-v6-buildxxxx-FORTINET.out – Normal FortiGate build, no built in wireless hardware at all. Serial number starts with FGT30E
- FWF_30E-v6-build0302-FORTINET.out – FortiWifi build – Normal FortiGate + 2.4/5 Ghz radios for A/B/G/N wireless. Serial number starts with: FWF30E

There is a wireless version for the MI and MN versions as well. Each one of these models are different hardware configurations.
One unit will NOT accept the firmware of another type due to hardware configuration.