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Stefano Babic0187c982013-06-27 11:42:38 +02001High Assurance Boot (HAB) for i.MX6 CPUs
2
3To authenticate U-Boot only by the CPU there is no code required in
4U-Boot itself. However, the U-Boot image to be programmed into the
5boot media needs to be properly constructed, i.e. it must contain a
6proper Command Sequence File (CSF).
7
8The Initial Vector Table contains a pointer to the CSF. Please see
9doc/README.imximage for how to prepare u-boot.imx.
10
11The CSF itself is being generated by Freescale HAB tools.
12
13mkimage will output additional information about "HAB Blocks"
14which can be used in the Freescale tooling to authenticate U-Boot
15(entries in the CSF file).
16
17Image Type: Freescale IMX Boot Image
18Image Ver: 2 (i.MX53/6 compatible)
19Data Size: 327680 Bytes = 320.00 kB = 0.31 MB
20Load Address: 177ff420
21Entry Point: 17800000
22HAB Blocks: 177ff400 00000000 0004dc00
Wolfgang Denk93e14592013-10-04 17:43:24 +020023 ^^^^^^^^ ^^^^^^^^ ^^^^^^^^
Stefano Babic0187c982013-06-27 11:42:38 +020024 | | |
25 | | -------- (1)
26 | |
27 | ------------------- (2)
28 |
29 --------------------------- (3)
30
31(1) Size of area in file u-boot.imx to sign
32 This area should include the IVT, the Boot Data the DCD
33 and U-Boot itself.
34(2) Start of area in u-boot.imx to sign
35(3) Start of area in RAM to authenticate
36
37CONFIG_SECURE_BOOT currently enables only an additional command
38'hab_status' in U-Boot to retrieve the HAB status and events. This
39can be useful while developing and testing HAB.
40
41Commands to generate a signed U-Boot using Freescale HAB tools:
42cst --o U-Boot_CSF.bin < U-Boot.CSF
43objcopy -I binary -O binary --pad-to 0x2000 --gap-fill=0x00 \
44 U-Boot_CSF.bin U-Boot_CSF_pad.bin
45cat u-boot.imx U-Boot_CSF_pad.bin > u-boot-signed.imx
46
47NOTE: U-Boot_CSF.bin needs to be padded to the value specified in
48the imximage.cfg file.