altos: Run self loader when application sets boot addr to 0

This causes the flash loader startup code to fall into the loader when
the application sets the boot address to zero.

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/src/stm/ao_interrupt.c b/src/stm/ao_interrupt.c
index 49156285..969e6a0f 100644
--- a/src/stm/ao_interrupt.c
+++ b/src/stm/ao_interrupt.c
@@ -42,10 +42,11 @@ const void *stm_interrupt_vector[];
 void start(void)
 {
 #ifdef AO_BOOT_CHAIN
-	ao_boot_check_chain();
-#endif
+	if (ao_boot_check_chain()) {
 #ifdef AO_BOOT_PIN
-	ao_boot_check_pin();
+		ao_boot_check_pin();
+#endif
+	}
 #endif
 	/* Set interrupt vector table offset */
 	stm_nvic.vto = (uint32_t) &stm_interrupt_vector;