Hard Drive Media Device Path - Intel Extensible Firmware Interface Specification

Extensible Firmware Interface Specification
Table 5-22. Hard Drive Media Device Path
Mnemonic
Type
Sub-Type
Length
Partition Number
Partition Start
Partition Size
Partition Signature
MBR Type
Signature Type
The following structure defines an MBR for EFI:
Typedef struct _MBR_PARTITION {
UINT8
UINT8
UINT8
UINT8
UINT32
UINT32
} MBR_PARTITION;
typedef struct _PC_MBR {
UINT8
MBR_PARTITION
UINT16
} PC_MBR;
130
Byte Byte
Offset Length Description
0 1 Type 4 – Media Device Path
1 1 Sub-Type 1 – Hard Drive
2 2 Length of this structure in bytes. Length is 42 bytes.
4 4 Partition Number of the hard drive. Partition numbers start
at one. Partition number zero represents the entire device.
Partitions are defined by entries in the master boot record in
the first sector of the hard disk device.
8 8 Starting LBA of the partition on the hard drive
16 8 Size of the partition in units of Logical Blocks
24 16 Signature unique to this partition
40 1 MBR Type: (Unused values reserved)
0x01 – PC AT compatible MBR. Partition Start and Partition
0x02 – EFI Partition Table Header.
41 1 Type of Disk Signature: (Unused values reserved)
0x00 – No Disk Signature.
0x01 – 32-bit signature from address 0x1b8 of the type
0x02 – GUID signature.
BootIndicator;
PartitionStartCHS[3];
OS_Indicator;
PartitionEndCHS[3];
PartitionStartingLBA;
PartitionSizeInLBA;
MBRCode[0x1BE];
PartitionEntry[4];
Signature;
12/12/00
Size come from
PartitionStartingLBA
for the partition.
PartitionSizeInLBA
0x01 MBR.
// 0x80 for active partition
// Must be 0xaa55
and
Version 1.02