diff --git a/boards/walkie_talkies.h b/boards/walkie_talkies.h
index cbc05a4..8c27e6c 100644
--- a/boards/walkie_talkies.h
+++ b/boards/walkie_talkies.h
@@ -1,6 +1,8 @@
 #ifndef _BOARDS_WALKIE_TALKIES
 #define _BOARDS_WALKIE_TALKIES
 
+#define PICO_FLASH_SIZE_BYTES (16*1024*1024)
+
 #include "boards/pico.h"
 
 #undef PICO_BOOT_STAGE2_CHOOSE_W25Q080