Download the latest zip with binaries for Windows from DmiDecode.

Run \sbin\dmidecode.exe with the following command:

dmidecode.exe -t 0

An example of output from an IBM x460. The BMC firmware is shown in the line “Firmware Revision” at the end.

# dmidecode 2.10
SMBIOS 2.5 present.

Handle 0x0000, DMI type 0, 24 bytes
BIOS Information
        Vendor: IBM
        Version: -[ZUE166AUS-1.12]-
        Release Date: 02/15/2008
        Address: 0xF0240
        Runtime Size: 64960 bytes
        ROM Size: 8192 kB
        Characteristics:
                PCI is supported
                BIOS is upgradeable
                BIOS shadowing is allowed
                Boot from CD is supported
                Selectable boot is supported
                Japanese floppy for NEC 9800 1.2 MB is supported (int 13h)
                Japanese floppy for Toshiba 1.2 MB is supported (int 13h)
                5.25"/360 kB floppy services are supported (int 13h)
                5.25"/1.2 MB floppy services are supported (int 13h)
                3.5"/720 kB floppy services are supported (int 13h)
                3.5"/2.88 MB floppy services are supported (int 13h)
                Print screen service is supported (int 5h)
                8042 keyboard services are supported (int 9h)
                Serial services are supported (int 14h)
                Printer services are supported (int 17h)
                CGA/mono video services are supported (int 10h)
                ACPI is supported
                USB legacy is supported
                I2O boot is supported
                LS-120 boot is supported
                Function key-initiated network boot is supported
                Targeted content distribution is supported
        BIOS Revision: 1.12
        Firmware Revision: 2.11

Source:developerWorks > IBM Systems > Forums > System x Server > BMC firmware version