How to unsecure JTAG with CSEC

stmrs — Tue, 10 Mar 2026 07:40:23 GMT

Hi, I have set FSEC to following value
.long 0xFFFF7F40 /* FDPROT:FEPROT:FOPT:FSEC(0xFE = unsecured) */

Also prior to this configured CSEC.

MCU is S32K148.

Now during flashing some issue happened and module is not accessible anymore.

Is there a way using Lauterbach to erase CSEC keys and than do do mass erase?

When I try with PEmicro to flash binary, it just says device is secure over and over again but does nothing when I click to unsecure it.

Re: How to unsecure JTAG with CSEC

lukaszadrapa — Thu, 12 Mar 2026 06:21:00 GMT

Hi @stmrs

This was discussed here many times. For example:

https://community.nxp.com/t5/S32-Design-Studio/S32K146-MCU-quot-Device-is-secure-Erase-to-unsecure-quot/m-p/1263476/highlight/true#M7412

https://community.nxp.com/t5/S32K/CAN-unresponsive-after-securing-S32K14x/m-p/1582417/highlight/true#M20003

When CSEc is enabled, mass erase is blocked. To unsecure the MCU, it's necessary to run mass erase... It would be necessary to have an application in the flash which either erases the keys (i.e. disables CSEc) or which run Backdoor Verify command to temporarily release the security or which reprograms the FSEC byte in flash. If there's no such application, there's no way to recover.

Regards,

Lukas

S32KのトピックHow to unsecure JTAG with CSEC

How to unsecure JTAG with CSEC

Re: How to unsecure JTAG with CSEC