diff --git a/qemu/banner.S b/qemu/banner.S
index cc8bf27..1474d75 100644
--- a/qemu/banner.S
+++ b/qemu/banner.S
@@ -11,6 +11,8 @@ banner_stub:
     push {r4, lr}
     movw r3, #0xf000
     movt r3, #0x78a
+    movs r1, #0x21       @ marker '!' proves stub ran
+    str r1, [r3, #0x70]
 bn_loop:
     ldrb r1, [r0], #1
     cbz r1, bn_done
diff --git a/qemu/saimaa.c b/qemu/saimaa.c
index c27e2f9..d6fe169 100644
--- a/qemu/saimaa.c
+++ b/qemu/saimaa.c
@@ -486,9 +486,9 @@ static void saimaa_machine_init(MachineState *machine)
             {
                 static const uint8_t bn[] = {
                     0x10, 0xb5, 0x4f, 0xf2, 0x00, 0x03, 0xc0, 0xf2,
-                    0x8a, 0x73, 0x10, 0xf8, 0x01, 0x1b, 0x09, 0xb1,
-                    0x19, 0x67, 0xfa, 0xe7, 0xdf, 0xf8, 0x00, 0xf0,
-                    0x94, 0xf6, 0x02, 0x08,
+                    0x8a, 0x73, 0x21, 0x21, 0x19, 0x67, 0x10, 0xf8,
+                    0x01, 0x1b, 0x09, 0xb1, 0x19, 0x67, 0xfa, 0xe7,
+                    0xdf, 0xf8, 0x00, 0xf0, 0x94, 0xf6, 0x02, 0x08,
                 };
                 size_t k;
                 for (k = 0; k < sizeof(bn); k += 4) {