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0892ff6418
This script is needed for packing EC binary into SPI flash for MEC1322. This includes adding tag and header at appropriate location and signing the image. Signing key, for obvious reason, is not included here until we are sure what key we want to check in. BUG=chrome-os-partner:24107 TEST=Build and boot on eval board BRANCH=None Change-Id: I92db7d2ba2c76c14a9c6611a04dbd6a2c3eb8d83 Signed-off-by: Vic (Chun-Ju) Yang <victoryang@chromium.org> Reviewed-on: https://chromium-review.googlesource.com/177324 Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
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.