diff --git a/Documentation/how-to-build.rst b/Documentation/how-to-build.rst
index da17ca9829536730a7b2134a5650f38d0c604d13..144c2e1f757b66fca5aff56255e2f851ec0b7ef7 100644
--- a/Documentation/how-to-build.rst
+++ b/Documentation/how-to-build.rst
@@ -68,6 +68,8 @@ firmware features:
 - ``-Ddebug_prints=true``: Print more verbose debugging log messages
 - ``-Dble_trace=true``: Enable BLE tracing.  This will output lots of status
   info related to BLE.
+- ``-Ddebug_core1=true``: Enable the core 1 SWD lines which are exposed on the
+  SAO connector.  Only use this if you have a debugger which is modified for core 1.
 
 .. warning::
 
diff --git a/epicardium/main.c b/epicardium/main.c
index 56f532a675960a4f86c375356ab795603a8f5c7b..dc3dfd25955fab8ea4682724e9f6af25ae539a0d 100644
--- a/epicardium/main.c
+++ b/epicardium/main.c
@@ -6,6 +6,7 @@
 #include "max32665.h"
 #include "uart.h"
 #include "cdcacm.h"
+#include "gpio.h"
 
 #include "card10.h"
 #include "pmic.h"
@@ -51,7 +52,24 @@ int main(void)
 	LOG_INFO("startup", "Version " CARD10_VERSION);
 
 	card10_init();
-	card10_diag();
+#ifdef CARD10_DEBUG_CORE1
+	LOG_WARN("startup", "Core 1 Debugger Mode");
+	static const gpio_cfg_t swclk = {
+		PORT_0,
+		PIN_7,
+		GPIO_FUNC_ALT3,
+		GPIO_PAD_NONE,
+	};
+	static const gpio_cfg_t swdio = {
+		PORT_0,
+		PIN_6,
+		GPIO_FUNC_ALT3,
+		GPIO_PAD_NONE,
+	};
+
+	GPIO_Config(&swclk);
+	GPIO_Config(&swdio);
+#endif /* CARD10_DEBUG_CORE1 */
 
 	gfx_copy_region_raw(
 		&display_screen, 0, 0, 160, 80, 2, (const void *)(Heart)
diff --git a/meson.build b/meson.build
index 3dd0578c22938b2bafa857aca91a2625f3b2ac0e..f1586ec93aa9aae174a8a26bc95d1cc708e0cea5 100644
--- a/meson.build
+++ b/meson.build
@@ -28,6 +28,13 @@ if get_option('debug_prints')
   )
 endif
 
+if get_option('debug_core1')
+  add_global_arguments(
+    ['-DCARD10_DEBUG_CORE1=1'],
+    language: 'c',
+  )
+endif
+
 add_global_link_arguments(
   '-Wl,--gc-sections',
   '-lm',
diff --git a/meson_options.txt b/meson_options.txt
index bb96608f53ba3363e9e5a3b96dfb6eb6e11086df..0bff7f441774f3f6eb695dd2f29fc308af3a0d44 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -6,6 +6,14 @@ option(
   description: 'Whether to print debug messages on the serial console'
 )
 
+option(
+  'debug_core1',
+  type: 'boolean',
+  value: false,
+
+  description: 'Enable core 1 debugging interface'
+)
+
 option(
   'ble_trace',
   type: 'boolean',