diff --git a/boards/t5-epaper-s3.json b/boards/t5-epaper-s3.json
index 8d47b1866..16106198e 100644
--- a/boards/t5-epaper-s3.json
+++ b/boards/t5-epaper-s3.json
@@ -8,7 +8,7 @@
     "core": "esp32",
     "extra_flags": [
       "-DBOARD_HAS_PSRAM",
-      "-DARDUINO_RUNNING_CORE=0",
+      "-DARDUINO_RUNNING_CORE=1",
       "-DARDUINO_EVENT_RUNNING_CORE=0",
       "-DARDUINO_USB_CDC_ON_BOOT=1",
       "-DARDUINO_USB_MODE=1"