iMX 8M Mini Secure boot time

[Mikalai]

I am working on hardening the iMX 8M Mini based device and experience problems with Secure boot.

Our requirement is to be able to boot within 100ms. But with Secure boot enabled we are getting 800ms boot time from Reset deassertion to early U-boot SPL, without Secure boot the boot time is 72ms. (Measured using GPIO pulses, according to AN13369 "i.MX 8 - Boot Time Measurements Methodology").

At the same time AN4581 "i.MX Secure Boot on HABv4 Supported Devices" says that with Fast autherntication feature "The typical boot time for an image smaller than 1 MB can be reduced from 25 ms to 12 ms."

Is there any instructions how to get boot time at least 25ms with secure boot enabled? Maybe i have missed something important?

[Harvey021]

Hi @Mikalai 

For fast authentication there are these steps that are different from normal verification.

1, The CA flag select "n" when you generate PKI tree. (introduction_habv4.txt\habv4\imx\doc - uboot-imx - i.MX U-Boot (codeaurora.org))

2, Configuration of csf for spl and fit, please refer to csf_uboot_fast_authentication.txt\mx6_mx7\csf_examples\habv4\imx\doc - uboot-imx - i.MX U-Boot (code...

Best regards

Harvey