biosdecode
Decode BIOS information
SYNOPSIS
biosdecode [-d] [-s] [-f file] [-h] [-V]
PARAMETERS
-d
Dump raw hexadecimal data from BIOS memory areas without decoding
-s
Limit decoding to SMBIOS structures only
-f file
Read BIOS data from file instead of /dev/mem
-h, --help
Display usage help and exit
-V, --version
Print program version and exit
DESCRIPTION
biosdecode is a command-line utility from the lm-sensors package that reads and decodes BIOS memory contents, focusing on SMBIOS (System Management BIOS) structures. These structures provide detailed hardware information supplied by the firmware, including BIOS vendor and version, system manufacturer, product name, UUID, serial numbers, baseboard (motherboard) details, chassis information, processor socket designations, memory module data, and more.
By default, it scans physical memory via /dev/mem to locate the SMBIOS entry point and parse subsequent tables into human-readable format. This is particularly useful for inventorying hardware configurations, troubleshooting firmware issues, or verifying OEM-specific data. Without options, it outputs decoded fields alongside memory offsets and raw data summaries.
The tool supports dumping raw hex data for analysis and can read from files for offline decoding. It requires root privileges due to direct memory access and is often used alongside sensors-detect for hardware monitoring setup. Note that modern systems may restrict /dev/mem access, favoring safer alternatives like sysfs-based tools.
CAVEATS
Requires root privileges (sudo). /dev/mem access often restricted on modern kernels for security (e.g., Grsecurity, UEFI Secure Boot). May fail on virtual machines or locked systems. Use dmidecode for safer sysfs-based decoding.
Verbose output; pipe to grep for specific data.
COMMON USE CASES
Hardware inventory (biosdecode | grep -i vendor); firmware debugging; offline analysis (biosdecode -f biosdump.bin)
SAMPLE OUTPUT STRUCTURE
# SMBios entry point at 0x<addr>
BIOS Information (Type 0): Vendor: Dell Inc., Version: A15, Release: 05/15/2019
System Information (Type 1): Manufacturer: Dell Inc., Product: OptiPlex 7050
Baseboard Information (Type 2): etc.
HISTORY
Part of lm-sensors project since ~2002 for hardware sensor detection. Evolved to support SMBIOS 2.x/3.x standards; maintained for legacy BIOS decoding as UEFI shifts to ACPI tables.
