1 High Assurance Boot (HAB) for i.MX6 CPUs
3 To authenticate U-Boot only by the CPU there is no code required in
4 U-Boot itself. However, the U-Boot image to be programmed into the
5 boot media needs to be properly constructed, i.e. it must contain a
6 proper Command Sequence File (CSF).
8 The Initial Vector Table contains a pointer to the CSF. Please see
9 doc/README.imximage for how to prepare u-boot.imx.
11 The CSF itself is being generated by Freescale HAB tools.
13 mkimage will output additional information about "HAB Blocks"
14 which can be used in the Freescale tooling to authenticate U-Boot
15 (entries in the CSF file).
17 Image Type: Freescale IMX Boot Image
18 Image Ver: 2 (i.MX53/6 compatible)
19 Data Size: 327680 Bytes = 320.00 kB = 0.31 MB
20 Load Address: 177ff420
22 HAB Blocks: 177ff400 00000000 0004dc00
23 ^^^^^^^^ ^^^^^^^^ ^^^^^^^^
27 | ------------------- (2)
29 --------------------------- (3)
31 (1) Size of area in file u-boot.imx to sign
32 This area should include the IVT, the Boot Data the DCD
34 (2) Start of area in u-boot.imx to sign
35 (3) Start of area in RAM to authenticate
37 CONFIG_SECURE_BOOT currently enables only an additional command
38 'hab_status' in U-Boot to retrieve the HAB status and events. This
39 can be useful while developing and testing HAB.
41 Commands to generate a signed U-Boot using Freescale HAB tools:
42 cst --o U-Boot_CSF.bin < U-Boot.CSF
43 objcopy -I binary -O binary --pad-to 0x2000 --gap-fill=0x00 \
44 U-Boot_CSF.bin U-Boot_CSF_pad.bin
45 cat u-boot.imx U-Boot_CSF_pad.bin > u-boot-signed.imx
47 NOTE: U-Boot_CSF.bin needs to be padded to the value specified in
48 the imximage.cfg file.