topic Re: S32K144EVB Secure Boot in S32K

S32K144EVB Secure Boot

bix010 — Thu, 26 Jul 2018 06:33:46 GMT

Hi,

I'm trying out the secure boot feature on the S32K144EVB board. I'm being careful, as I don't want to brick the board. I'm seeing two different options for boot size:

1. In the sample code provided in AN5401SW, example #4 shows how to configure secure boot manually. It sets the BOOT_SIZE to 128*1024*8.

2. In the SDK code for CSEC module provided by Processor Expert, the comments indicate the bootSize is the number of blocks of 128-bit data to check on boot. Maximum size is 512KB.

Based on (2), would the maximum bootSize be equals to (512KB / 128bit) = 4096?

But in (1), the BOOT_SIZE is defined as 128*1024*8 = 1,048,576.

What is the correct way to calculate the boot size?

Thanks!

Re: S32K144EVB Secure Boot

fuzeng — Thu, 16 Aug 2018 06:50:09 GMT

the 512K is a read parittion, cmac can't caculate over a partition.

caculate:

16byte=128bits/8bits

512*1024byte/16byte=32768 blocks.(max)

Re: S32K144EVB Secure Boot

bix010 — Mon, 20 Aug 2018 13:33:22 GMT

Hi,

I tried and the BOOT_SIZE is counted in number of bits, rounded up to the nearest 128-bits. i.e. Option (1) in my original post.