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| -rw-r--r-- | doc/README.chromium | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/doc/README.chromium b/doc/README.chromium index c56545cb7f..75f2f24042 100644 --- a/doc/README.chromium +++ b/doc/README.chromium @@ -27,6 +27,9 @@ available: since many of them only support coreboot as the bootloader and have no bare-metal support in U-Boot. For this, use the 'coreboot' target. + - Running U-Boot and booting into a Chrome OS image, but without verified + boot. This can be useful for testing. + U-Boot with Chromium OS verified boot ------------------------------------- @@ -175,6 +178,35 @@ course the above sandbox feature provides a sort of functional test and can detect problems that affect the flow or particular vboot features. +U-Boot without Chromium OS verified boot +---------------------------------------- + +The following script can be used to boot a Chrome OS image on coral: + + # Read the image header and obtain the address of the kernel + # The offset 4f0 is defined by verified boot and may change for other + # Chromebooks + read mmc 2:2 100000 0 80; setexpr loader *001004f0; + + # Get the kernel size and calculate the number of blocks (0x200 bytes each) + setexpr size *00100518; setexpr blocks $size / 200; + + # Read the full kernel and calculate the address of the setup block + read mmc 2:2 100000 80 $blocks; setexpr setup $loader - 1000; + + # Locate the command line + setexpr cmdline $loader - 2000; + + # Start the zboot process with the loaded kernel, setup block and cmdline + zboot start 100000 0 0 0 $setup $cmdline; + + # Load the kernel, fix up the 'setup' block, dump information + zboot load; zboot setup; zboot dump + + # Boot into Chrome OS + zboot go + + TO DO ----- |