Attribute bits, all bits reserved by UEFI
Bit 0: If this bit is set, the partition is required for the platform to function. The owner/creator of the
partition indicates that deletion or modification of the contents can result in loss of platform
features or failure for the platform to boot or operate. The system cannot function normally if
this partition is removed, and it should be considered part of the hardware of the system.
Actions such as running diagnostics, system recovery, or even OS install or boot, could
potentially stop working if this partition is removed. Unless OS software or firmware
recognizes this partition, it should never be removed or modified as the UEFI firmware or
platform hardware may become non-functional.
Bit 1: If this bit is set, then firmware must not produce an EFI_BLOCK_IO_PROTOCOL device for
this partition. By not producing an EFI_BLOCK_IO_PROTOCOL partition, file system
mappings will not be created for this partition in UEFI.
Bit 2: This bit is set aside to let systems with traditional PC-AT BIOS firmware implementations
inform certain limited, special-purpose software running on these systems that a GPT
partition may be bootable. The UEFI boot manager must ignore this bit when selecting
a UEFI-compliant application, e.g., an OS loader.
Bits 3-47: Undefined and must be zero. Reserved for expansion by future versions of the UEFI
specification.
Bits 48-63: Reserved for GUID specific use. The use of these bits will vary depending on the
PartitionTypeGUID. Only the owner of the PartitionTypeGUID is allowed
to modify these bits. They must be preserved if Bits 0-47 are modified..
Attribute bits, all bits reserved by UEFI Bit 0: If this bit is set, the partition is required for the platform to function. The owner/creator of the partition indicates that deletion or modification of the contents can result in loss of platform features or failure for the platform to boot or operate. The system cannot function normally if this partition is removed, and it should be considered part of the hardware of the system. Actions such as running diagnostics, system recovery, or even OS install or boot, could potentially stop working if this partition is removed. Unless OS software or firmware recognizes this partition, it should never be removed or modified as the UEFI firmware or platform hardware may become non-functional. Bit 1: If this bit is set, then firmware must not produce an EFI_BLOCK_IO_PROTOCOL device for this partition. By not producing an EFI_BLOCK_IO_PROTOCOL partition, file system mappings will not be created for this partition in UEFI. Bit 2: This bit is set aside to let systems with traditional PC-AT BIOS firmware implementations inform certain limited, special-purpose software running on these systems that a GPT partition may be bootable. The UEFI boot manager must ignore this bit when selecting a UEFI-compliant application, e.g., an OS loader. Bits 3-47: Undefined and must be zero. Reserved for expansion by future versions of the UEFI specification. Bits 48-63: Reserved for GUID specific use. The use of these bits will vary depending on the PartitionTypeGUID. Only the owner of the PartitionTypeGUID is allowed to modify these bits. They must be preserved if Bits 0-47 are modified..