Intel® Core™ Ultra Processor
Datasheet, Volume 1 of 2
Supporting Intel® Core™ Ultra Processor for U/H-series Platforms, formerly known as Meteor Lake
| ID | Date | Version | Classification |
|---|---|---|---|
| 792044 | 12/15/2023 | Public |
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Boot Block Update Scheme
The
For SPI when top swap is enabled, the behavior is as described below. When the Top Swap Enable bit is 0, the
The scheme is based on the concept that the top block is reserved as the “boot” block, and the block immediately below the top block is reserved for doing boot-block updates.
- Software copies the top block to the block immediately below the top
- Software checks that the copied block is correct. This could be done by performing a checksum calculation.
- Software sets the “Top-Block Swap” bit. This will invert the appropriate address bits for the cycles going to the SPI.
- Software erases the top block
- Software writes the new top block
- Software checks the new top block
- Software clears the top-block swap bit
- Software sets the Top_Swap Lock-Down bit
If a power failure occurs at any point after step 3, the system will be able to boot from the copy of the boot block that is stored in the block below the top. This is because the top-swap bit is backed in the RTC well.