AnsweredAssumed Answered

flash is secured but flash config field is not

Question asked by roymessinger on Jan 16, 2018
Latest reply on Jan 18, 2018 by Kerry Zhou

I'm having a very strange issue.

Even though the Flash Configuration Field (FCF) is at its default state:

/* Flash Configuration*/
.section .FlashConfig, "a"
.long 0xFFFFFFFF
.long 0xFFFFFFFF
.long 0xFFFFFFFF
.long 0xFFFFFFFE

Whenever I try to flash my (custom) board with Segger J-link I'm getting a secure alert (stating that the image causes the flash to be secured), and obviously when trying to delete app later on with KBOOT, I'm getting a message saying flash cannot be deleted since it is secured. This pop up is shown also with a 'regular app' located at address 0x00 (so no connection to KBOOT).

But,

when changing the FCF to the following:

/* Flash Configuration*/
.section .FlashConfig, "a"
.long 0xFFFFFFFF
.long 0xFFFFFFFF
.long 0xFFFFFFFF
.long 0xFFFFFFFF

I am not receiving the message and the flash is not secured and can later be deleted successfully.

This is totally opposite than it should be, as I understand (also clearly explained here: https://www.nxp.com/docs/en/application-note/AN4835.pdf )

 

So, what is going on?

Outcomes