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+-------------------+
u16 | type = 1 |
u16 | flags |
u32 | size |
u32[n] | mbi_tag_types |
+-------------------+
‘mbi_tag_types’ is an array of u32’s, each one representing an information request.
If this tag is present and ‘optional’ is set to ‘0’, the bootloader must support the requested tag and be able to provide relevant information to the image if it is available. If the bootloader does not understand the meaning of the requested tag it must fail with an error. However, if it supports a given tag but the information conveyed by it is not available the bootloader does not provide the requested tag in the Multiboot2 information structure and passes control to the loaded image as usual.
Note: The above means that there is no guarantee that any tags of type ‘mbi_tag_types’ will actually be present. E.g. on a videoless system even if you requested tag ‘8’ and the bootloader supports it, no tags of type ‘8’ will be present in the Multiboot2 information structure.