Signed-off-by: Sven Ebenfeld sven.ebenfeld@gmail.com --- doc/README.imx6 | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+)
diff --git a/doc/README.imx6 b/doc/README.imx6 index 73b8b0b..add1d80 100644 --- a/doc/README.imx6 +++ b/doc/README.imx6 @@ -138,3 +138,51 @@ c The last "c" command tells kermit (from ckermit package in most distros) to switch from command line mode to communication mode, and when the script is finished, the U-Boot prompt is shown in the same shell. + +3. Using Secure Boot on i.MX6 machines with SPL support +------------------------------------------------------- + +This version of U-Boot is able to build a signable version of the SPL +as well as a signable version of the U-Boot image. The signature can +be verified through High Assurance Boot (HAB). + +CONFIG_SECURE_BOOT is needed to build those two binaries. +After building, you need to create a command sequence file and use +Freescales Code Signing Tool to sign both binaries. After creation, +the mkimage tool outputs the required information about the HAB Blocks +parameter for the CSF. + +More information about the CSF and HAB can be found in the AN4581. +https://cache.freescale.com/files/32bit/doc/app_note/AN4581.pdf + +We don't want to explain how to create a PKI tree or SRK table as +this is well explained in the Application Note. + +Example Output of the SPL (imximage) creation: + Image Type: Freescale IMX Boot Image + Image Ver: 2 (i.MX53/6/7 compatible) + Mode: DCD + Data Size: 61440 Bytes = 60.00 kB = 0.06 MB + Load Address: 00907420 + Entry Point: 00908000 + HAB Blocks: 00907400 00000000 0000cc00 + +Example Output of the u-boot-ivt.img (firmware_ivt) creation: + Image Name: U-Boot 2016.11-rc1-31589-g2a4411 + Created: Sat Nov 5 21:53:28 2016 + Image Type: ARM U-Boot Firmware with HABv4 IVT (uncompressed) + Data Size: 352192 Bytes = 343.94 kB = 0.34 MB + Load Address: 17800000 + Entry Point: 00000000 + HAB Blocks: 0x177fffc0 0x0000 0x00054020 + +The CST (Code Signing Tool) can be downloaded from NXP. +# Compile CSF and create signature +./cst --o csf-u-boot.bin < command_sequence_uboot.csf +./cst --o csf-SPL.bin < command_sequence_spl.csf +# Append compiled CSF to Binary +cat SPL csf-SPL.bin > SPL-signed +cat u-boot-ivt.img csf-u-boot.bin > u-boot-signed.img + +These two signed binaries can be used on an i.MX6 in closed +configuration when the according SRK Table Hash has been flashed. \ No newline at end of file