Cortex A9 core locks and cant't stop it

Device: Cyclone V SoC (Dual Cortex A9)

Baremetal code with RTOS

Hi,

When trying to debug a code inside DS-5 I get the following message:

ERROR(TAD9-NAL30):
! Unable to stop device Cortex-A9 SMP
! Cannot stop target.
WARNING(CMD570): The target was unable to reach the expected execution status

Cortex-A9-0 is listed as running, Cortex-A9-1 is stopped(SYS)

This does not allow me to do some debuging. There is no Trace interface only JTAG. Core A9-1 can be stopped and controlled.

What could be causing the core not to be able to stop? How can I force it?

thanks,

-Galo