diff --git a/10.02_devices/2_src/cpu20/ka11.c b/10.02_devices/2_src/cpu20/ka11.c
index fdc8e35..d19e366 100644
--- a/10.02_devices/2_src/cpu20/ka11.c
+++ b/10.02_devices/2_src/cpu20/ka11.c
@@ -553,6 +553,7 @@ step(KA11 *cpu)
 	case 2:	TR(RTI);
 		BA = SP; POP; IN(PC);
 		BA = SP; POP; IN(PSW);
+		levelchange(cpu->psw) ;
 		SVC;
 	case 3:	TR(BPT); TRAP(014);
 	case 4:	TR(IOT); TRAP(020);