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+High Assurance Boot (HAB) for i.MX6 CPUs
+
+To authenticate U-Boot only by the CPU there is no code required in
+U-Boot itself. However, the U-Boot image to be programmed into the
+boot media needs to be properly constructed, i.e. it must contain a
+proper Command Sequence File (CSF).
+
+The Initial Vector Table contains a pointer to the CSF. Please see
+doc/README.imximage for how to prepare u-boot.imx.
+
+The CSF itself is being generated by Freescale HAB tools.
+
+mkimage will output additional information about "HAB Blocks"
+which can be used in the Freescale tooling to authenticate U-Boot
+(entries in the CSF file).
+
+Image Type: Freescale IMX Boot Image
+Image Ver: 2 (i.MX53/6 compatible)
+Data Size: 327680 Bytes = 320.00 kB = 0.31 MB
+Load Address: 177ff420
+Entry Point: 17800000
+HAB Blocks: 177ff400 00000000 0004dc00
+ ^^^^^^^^ ^^^^^^^^ ^^^^^^^^
+ | | |
+ | | -------- (1)
+ | |
+ | ------------------- (2)
+ |
+ --------------------------- (3)
+
+(1) Size of area in file u-boot.imx to sign
+ This area should include the IVT, the Boot Data the DCD
+ and U-Boot itself.
+(2) Start of area in u-boot.imx to sign
+(3) Start of area in RAM to authenticate
+
+CONFIG_SECURE_BOOT currently enables only an additional command
+'hab_status' in U-Boot to retrieve the HAB status and events. This
+can be useful while developing and testing HAB.
+
+Commands to generate a signed U-Boot using Freescale HAB tools:
+cst --o U-Boot_CSF.bin < U-Boot.CSF
+objcopy -I binary -O binary --pad-to 0x2000 --gap-fill=0x00 \
+ U-Boot_CSF.bin U-Boot_CSF_pad.bin
+cat u-boot.imx U-Boot_CSF_pad.bin > u-boot-signed.imx
+
+NOTE: U-Boot_CSF.bin needs to be padded to the value specified in
+the imximage.cfg file.