Highlight the System Project, and under FLOW, select Debug and Open Settings. Then select New Launch Configuration
Select the Enable Cross Triggering as shown below
Select Cross Triggering Breakpoints, and Add Item and configurate as shown below. For example, here we want to trigger the Cortex a53 #1 when there is a breakpoint on Cortex a53 #0
Select the Debug icon to launch the debug
In the Debug View, highlight the Cortex-A53 #1 and select Continue (play icon). This will result in the hello world is a loop
Highlight the Cortex-A53 #0 and add a breakpoint at line 29
Select Continue (play icon), and this should result in the breakpoint hit on the Cortex-a53 #1. Here, you can see that when the breakpoint hit on the first processor, it halted the second processor.