Optional data is binary data placed in the PDI after the image header table (IHT). You can include your own optional data like data, version, and so on. For more information, refer to optionaldata. This data is authenticated as part of IHT Signature and IHT is added as additional authenticated data (AAD) for the first secure header (SH) of the image header (IH) during encryption along with IHT. This implies that the optional data content remains as plain text.
As part of Authentication Optimization, for partitions that use the same authentication keys, the partition hashes are placed as part of Optional Data. For more information, see Authentication Optimization.
Bootgen accepts user and multiple optional data. For information on adding optional data, see optionaldata.
| Offset | Name | Description |
|---|---|---|
| 0x0 | ID | The Data IDs from 0x0 to 0x20 for Optional Data are
reserved for internal use. User Optional Data ID can be anything >
0x20. 0 - None, can be used for padding 1 - PLM Build Time Configuration Metadata as defined in the PLM Configuration document 2 - Data structure version information used in In-Place PLM Update Compatibility Check 3 - Hash Table for authentication optimization 4 - Indicates presence of PSMFW |
| 0x2 | Size | Total optional data size in words |
| 0x4 | Data | Actual data including padding |
| Last | Checksum | Sum of all the previous words in this data structure |