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Diffstat (limited to 'doc/README.gpt')
| -rw-r--r-- | doc/README.gpt | 41 |
1 files changed, 40 insertions, 1 deletions
diff --git a/doc/README.gpt b/doc/README.gpt index 35902ce0c88..a6f6de6a0f5 100644 --- a/doc/README.gpt +++ b/doc/README.gpt @@ -142,6 +142,10 @@ of the Primary. Attribute flags: Bit 0 - System partition + Bit 1 - Hide from EFI + Bit 2 - Legacy BIOS bootable + Bit 48-63 - Defined and used by the individual partition type + For Basic data partition : Bit 60 - Read-only Bit 62 - Hidden Bit 63 - Not mount @@ -161,16 +165,51 @@ To restore GUID partition table one needs to: The fields 'name' and 'size' are mandatory for every partition. The field 'start' is optional. + If field 'size' of the last partition is 0, the partiton is extended + up to the end of the device. + 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. + The field 'bootable' is optional, it is used to mark the GPT partition + bootable (set attribute flags "Legacy BIOS bootable"). + "name=u-boot,size=60MiB;name=boot,size=60Mib,bootable;name=rootfs,size=0" + It can be used to locate bootable disks with command + "part list <interface> <dev> -bootable <varname>", + please check out doc/README.distro for use. + 2. Define 'CONFIG_EFI_PARTITION' and 'CONFIG_CMD_GPT' -2. From u-boot prompt type: +3. From u-boot prompt type: gpt write mmc 0 $partitions +Checking (validating) GPT partitions in U-Boot: +=============================================== + +Procedure is the same as above. The only change is at point 3. + +At u-boot prompt one needs to write: + gpt verify mmc 0 [$partitions] + +where [$partitions] is an optional parameter. + +When it is not provided, only basic checks based on CRC32 calculation for GPT +header and PTEs are performed. +When provided, additionally partition data - name, size and starting +offset (last two in LBA) - are compared with data defined in '$partitions' +environment variable. + +After running this command, return code is set to 0 if no errors found in +on non-volatile medium stored GPT. + +Following line can be used to assess if GPT verification has succeed: + +U-BOOT> gpt verify mmc 0 $partitions +U-BOOT> if test $? = 0; then echo "GPT OK"; else echo "GPT ERR"; fi + + Partition type GUID: ==================== |