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8980e9a53a
Since we already created the firmware-nyan-5771.B branch, we can remove this from ToT now. But for sure we are still able to cherry-pick changes back to ToT or from ToT. BUG=none BRANCH=tot TEST=make buildall Change-Id: I637d27b9f8672c5d17b60e210a5211ab8e19b54a Signed-off-by: Louis Yung-Chieh Lo <yjlou@chromium.org> Reviewed-on: https://chromium-review.googlesource.com/197165
In the most general case, the flash layout looks something like this: +---------------------+ | Reserved for EC use | +---------------------+ +---------------------+ | Vblock B | +---------------------+ | RW firmware B | +---------------------+ +---------------------+ | Vblock A | +---------------------+ | RW firmware A | +---------------------+ +---------------------+ | FMAP | +---------------------+ | Public root key | +---------------------+ | Read-only firmware | +---------------------+ BIOS firmware (and kernel) put the vblock info at the start of each image where it's easy to find. The Blizzard EC expects the firmware vector table to come first, so we have to put the vblock at the end. This means we have to know where to look for it, but that's built into the FMAP and the RO firmware anyway, so that's not an issue. The RO firmware doesn't need a vblock of course, but it does need some reserved space for vboot-related things. Using SHA256/RSA4096, the vblock is 2468 bytes (0x9a4), while the public root key is 1064 bytes (0x428) and the current FMAP is 644 bytes (0x284). If we reserve 4K at the top of each FW image, that should give us plenty of room for vboot-related stuff.