In my work to port TF-M to IAR EWARM I have now gotten the MPC set up so that the startup will properly switch to the NS code.

I'm now running into an issue where I get a SecureFault when attempting to start the OS.

The idle and timer threads have been configured and the timer thread has been put on run.curr and SVC_Exit issues a BX LR, which results in a SecureFault.

SFSR indicates that it is an INVER (Invalid Exception Return): --- Invalid exception return flag. This can be caused by EXC_RETURN.DCRS being set to 0 when returning from an exception in the Non-secure state, or by EXC_RETURN.ES being set to 1 when returning from an exception in the Non-secure state. The possible values of this bit are: 0 Error has not occurred. 1 Error has occurred.