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👢 Detect UEFI or BIOS
Tuesday 28 February 2023 5 versions

Here is how you can detect if you’ve booted your computer using a UEFI BIOS or a Legacy BIOS. First, install the `dmidecode` utility from your operating system repository. On Debian, you can:

    1apt-get install dmidecode

`dmidecode` reports information related to the BIOS under a type 0 entry. A quick way to detect the BIOS mode is:

    1sudo dmidecode -t 0 | grep UEFI > /dev/null && echo UEFI || echo BIOS

On a (Legacy) BIOS system you would see:

     1$ sudo dmidecode -t 0
     2# dmidecode 3.4
     3Getting SMBIOS data from sysfs.
     4SMBIOS 3.0.0 present.
     5
     6Handle 0x0000, DMI type 0, 26 bytes
     7BIOS Information
     8        Vendor: 3mdeb
     9        Version: Dasharo (coreboot+SeaBIOS)
    10        Release Date: 08/23/2022
    11        ROM Size: 12 MB
    12        Characteristics:
    13                PCI is supported
    14                PC Card (PCMCIA) is supported
    15                BIOS is upgradeable
    16                Selectable boot is supported
    17                ACPI is supported
    18                Targeted content distribution is supported
    19        BIOS Revision: 0.0
    20        Firmware Revision: 0.0

On a UEFI system you would see:

     1$ sudo dmidecode -t 0
     2# dmidecode 3.4
     3Getting SMBIOS data from sysfs.
     4SMBIOS 3.1.1 present.
     5
     6Handle 0x0000, DMI type 0, 26 bytes
     7BIOS Information
     8        Vendor: American Megatrends Inc.
     9        Version: 2202
    10        Release Date: 07/14/2020
    11        Address: 0xF0000
    12        Runtime Size: 64 kB
    13        ROM Size: 16 MB
    14        Characteristics:
    15                PCI is supported
    16                APM is supported
    17                BIOS is upgradeable
    18                BIOS shadowing is allowed
    19                Boot from CD is supported
    20                Selectable boot is supported
    21                BIOS ROM is socketed
    22                EDD is supported
    23                Print screen service is supported (int 5h)
    24                8042 keyboard services are supported (int 9h)
    25                Serial services are supported (int 14h)
    26                Printer services are supported (int 17h)
    27                ACPI is supported
    28                USB legacy is supported
    29                BIOS boot specification is supported
    30                Targeted content distribution is supported
    31                UEFI is supported
    32        BIOS Revision: 5.13

#uefi #seabios #coreboot #bios 👢

# See Also

- 🔁 Migrate from UEFI to (Legacy) BIOS Tuesday 28 February 2023