cst

4 posts tagged cst, newest first.

Tagged cst

4 posts
01 Jun 2026
3 min

Signing the Nerves kernel on i.MX8M Plus, clean on the first try

The same kernel-signing procedure as track A, on a different build — and it passed first time, because the two things that went wrong last time were checked rather than assumed. A 691,712-byte padding gap, and a signed range that goes through the IVT.

cstembeddedhabimx8nervessecure-boot
27 Apr 2026
6 min

Signing the kernel, and a HAB failure the chip caught

Extending the chain from the bootloader to the kernel. The first signed Image failed with HAB_INV_ASSERTION — because I read NXP's own diagram literally and stopped the signed range one IVT short. How I decoded the event by hand and found the off-by-32-bytes.

cstembeddedhabimx8kernellinuxsecure-boot
20 Apr 2026
7 min

Signing imx-boot and turning on HAB on the i.MX8M Plus

Enabling CONFIG_IMX_HAB overflowed the SPL's SRAM budget by 10,440 bytes. Fixing that, computing the real CSF insertion offsets from the build's own binman node rather than NXP's generic one, signing with cst, and getting 'No HAB Events Found!' on hardware.

cstembeddedhabimx8secure-bootu-boot
16 Mar 2026
5 min

Generating HAB keys with NXP's Code Signing Tool (CST 4.0.1)

Getting CST, generating the thirteen-key HAB PKI tree with hab4_pki_tree.sh, and building the SRK table and its fuse hash with srktool. Including the thing that script does silently if you do not read it first: it invents a passphrase for you, and the passphrase is 'test'.

cryptographycstembeddedhabimx8secure-boot