|Partition n |
| |
----------------------------------------------------------
- LBA -34 |Entry 1|Entry 2| Entry 3| Entry 4| Secondary
- -------------------------------------------------- (bkp)
- LBA -33 |Entries 5 - 128 | GPT
+ LBA -34 |Entry 1|Entry 2| Entry 3| Entry 4| Backup
+ -------------------------------------------------- GPT
+ LBA -33 |Entries 5 - 128 |
| |
| |
LBA -2 | |
--------------------------------------------------
- LBA -1 |Secondary GPT Header |
+ LBA -1 |Backup GPT Header |
----------------------------------------------------------
For a legacy reasons, GPT's LBA 0 sector has a MBR structure. It is called
"LBA -1" means the last addressable block (in the mmc subsystem:
"dev_desc->lba - 1")
-Primary/Secondary GPT header:
+Primary/Backup GPT header:
----------------------------
Offset Size Description
GPT headers and partition entries are protected by CRC32 (the POSIX CRC32).
-Primary GPT header and Secondary GPT header have swapped values of "Current LBA"
+Primary GPT header and Backup GPT header have swapped values of "Current LBA"
and "Backup LBA" and therefore different CRC32 check-sum.
CRC32 for GPT headers (field "CRC of header") are calculated up till
the whole array entry ( Number_of_partition_entries *
sizeof(partition_entry_size (usually 128)))
-Observe, how Secondary GPT is placed in the memory. It is NOT a mirror reflect
+Observe, how Backup GPT is placed in the memory. It is NOT a mirror reflect
of the Primary.
Partition Entry Format:
"partitions=uuid_disk=${uuid_gpt_disk};name=${uboot_name},
size=${uboot_size},uuid=${uboot_uuid};"
- Fields 'name', 'size' and 'uuid' are mandatory for every partition.
+ The fields 'name' and 'size' are mandatory for every partition.
The field 'start' is optional.
- option: CONFIG_RANDOM_UUID
- If any partition "UUID" no exists then it is randomly generated.
+ The fields 'uuid' and 'uuid_disk' are optional if CONFIG_RANDOM_UUID is
+ enabled. A random uuid will be used if omitted or they point to an empty/
+ non-existent environment variable. The environment variable will be set to
+ the generated UUID.
2. Define 'CONFIG_EFI_PARTITION' and 'CONFIG_CMD_GPT'