How do I get dmidecode?

I use it in my BIOS Update add-on. Easiest way to get it, you can install that add-on, and it will be left in /usr/sbin/dmidecode.
The add-on does no harm, if there is a BIOS available for your system board it will be updated, otherwise it exits.

http://www.readynas.com/download/addons ... .5-x86.bin

edit:
Or skip the add-on, and grab it directly:

# wget --no-check-certificate "https://dl.dropbox.com/s/wcbf6kiry1le87o/dmidecode?dl=1"

# /usr/sbin/dmidecode 
# dmidecode 2.8
SMBIOS 2.6 present.
17 structures occupying 1007 bytes.
Table at 0x000FBDD0.

Handle 0x0000, DMI type 0, 24 bytes
BIOS Information
	Vendor: American Megatrends Inc.
	Version: 080016 
	Release Date: 08/23/2011
	Address: 0xF0000
	Runtime Size: 64 kB
	ROM Size: 2048 kB
	Characteristics:
		ISA is supported
		PCI is supported
		PNP is supported
		BIOS is upgradeable
		BIOS shadowing is allowed
		ESCD support is available
		Boot from CD is supported
		Selectable boot is supported
		BIOS ROM is socketed
		EDD is supported
		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
		LS-120 boot is supported
		ATAPI Zip drive boot is supported
		BIOS boot specification is supported
		Targeted content distribution is supported
	BIOS Revision: 8.16

Handle 0x0001, DMI type 1, 27 bytes
System Information
	Manufacturer: NETGEAR 
	Product Name: ReadyNAS
	Version: 08/23/2011 ReadyNAS-NVX-V2 V1.10
	Serial Number:                       
	UUID: 
	Wake-up Type: Power Switch
	SKU Number:                       
	Family:                      

Handle 0x0002, DMI type 2, 15 bytes
Base Board Information
	Manufacturer: NETGEAR
	Product Name: ReadyNAS 
	Version:                      
	Serial Number:                      
	Asset Tag:                      
	Features:
		Board is a hosting board
		Board is replaceable
	Location In Chassis:                      
	Chassis Handle: 0x0003
	Type: Motherboard
	Contained Object Handles: 0

Handle 0x0003, DMI type 3, 21 bytes
Chassis Information
	Manufacturer: NETGEAR
	Type: Desktop
	Lock: Not Present
	Version:                      
	Serial Number:                      
	Asset Tag:                      
	Boot-up State: Safe
	Power Supply State: Safe
	Thermal State: Safe
	Security Status: None
	OEM Information: 0x00000000
	Heigth: Unspecified
	Number Of Power Cords: 1
	Contained Elements: 0

Handle 0x0004, DMI type 4, 42 bytes
Processor Information
	Socket Designation: CPU 1
	Type: Central Processor
	Family: <OUT OF SPEC>
	Manufacturer: Intel            
	ID: CA 06 01 00 FF FB EB BF
	Version: Intel(R) Atom(TM) CPU D410   @ 1.66GHz              
	Voltage: 1.2 V
	External Clock: 167 MHz
	Max Speed: 1750 MHz
	Current Speed: 1666 MHz
	Status: Populated, Enabled
	Upgrade: <OUT OF SPEC>
	L1 Cache Handle: 0x0005
	L2 Cache Handle: 0x0006
	L3 Cache Handle: Not Provided
	Serial Number: To Be Filled By O.E.M.
	Asset Tag: To Be Filled By O.E.M.
	Part Number: To Be Filled By O.E.M.

Handle 0x0005, DMI type 7, 19 bytes
Cache Information
	Socket Designation: L1-Cache
	Configuration: Enabled, Not Socketed, Level 1
	Operational Mode: Write Back
	Location: Internal
	Installed Size: 24 KB
	Maximum Size: 24 KB
	Supported SRAM Types:
		Other
	Installed SRAM Type: Other
	Speed: Unknown
	Error Correction Type: Parity
	System Type: Data
	Associativity: Other

Handle 0x0006, DMI type 7, 19 bytes
Cache Information
	Socket Designation: L2-Cache
	Configuration: Enabled, Not Socketed, Level 2
	Operational Mode: Write Back
	Location: Internal
	Installed Size: 512 KB
	Maximum Size: 512 KB
	Supported SRAM Types:
		Other
	Installed SRAM Type: Other
	Speed: Unknown
	Error Correction Type: Single-bit ECC
	System Type: Unified
	Associativity: 8-way Set-associative

Handle 0x0007, DMI type 13, 22 bytes
BIOS Language Information
	Installable Languages: 1
		en|US|iso8859-1
	Currently Installed Language: en|US|iso8859-1

Handle 0x0008, DMI type 15, 35 bytes
System Event Log
	Area Length: 4 bytes
	Header Start Offset: 0x0000
	Header Length: 2 bytes
	Data Start Offset: 0x0002
	Access Method: Indexed I/O, one 16-bit index port, one 8-bit data port
	Access Address: Index 0x046A, Data 0x046C
	Status: Invalid, Not Full
	Change Token: 0x00000000
	Header Format: No Header
	Supported Log Type Descriptors: 6
	Descriptor 1: End of log
	Data Format 1: OEM-specific
	Descriptor 2: End of log
	Data Format 2: OEM-specific
	Descriptor 3: End of log
	Data Format 3: OEM-specific
	Descriptor 4: End of log
	Data Format 4: OEM-specific
	Descriptor 5: End of log
	Data Format 5: OEM-specific
	Descriptor 6: End of log
	Data Format 6: OEM-specific

Handle 0x0009, DMI type 16, 15 bytes
Physical Memory Array
	Location: System Board Or Motherboard
	Use: System Memory
	Error Correction Type: None
	Maximum Capacity: 2 GB
	Error Information Handle: Not Provided
	Number Of Devices: 1

Handle 0x000A, DMI type 19, 15 bytes
Memory Array Mapped Address
	Starting Address: 0x00000000000
	Ending Address: 0x000FFFFFFFF
	Range Size: 4 GB
	Physical Array Handle: 0x0009
	Partition Width: 0

Handle 0x000B, DMI type 17, 28 bytes
Memory Device
	Array Handle: 0x0009
	Error Information Handle: Not Provided
	Total Width: 64 bits
	Data Width: 64 bits
	Size: 4096 MB
	Form Factor: DIMM
	Set: None
	Locator: DIMM0
	Bank Locator: BANK0
	Type: DDR2
	Type Detail: Synchronous
	Speed: 667 MHz (1.5 ns)
	Manufacturer:               
	Serial Number: 00000000
	Asset Tag:             
	Part Number: PSD24G6672S       

Handle 0x000C, DMI type 20, 19 bytes
Memory Device Mapped Address
	Starting Address: 0x00000000000
	Ending Address: 0x000FFFFFFFF
	Range Size: 4 GB
	Physical Device Handle: 0x000B
	Memory Array Mapped Address Handle: 0x000A
	Partition Row Position: 1
	Interleaved Data Depth: 1

Handle 0x000D, DMI type 32, 20 bytes
System Boot Information
	Status: No errors detected

Handle 0x000E, DMI type 41, 11 bytes
Unknown Type
	Header and Data:
		29 0B 0E 00 01 83 00 FF FF FF FF
	Strings:
		To Be Filled By O.E.M.

Handle 0x000F, DMI type 41, 11 bytes
Unknown Type
	Header and Data:
		29 0B 0F 00 01 04 00 FF FF FF FF
	Strings:
		To Be Filled By O.E.M.

Handle 0x0010, DMI type 127, 4 bytes
End Of Table