diff --git a/common/bootloader.c b/common/bootloader.c
index f9802d36c5..43a7e47ce2 100644
--- a/common/bootloader.c
+++ b/common/bootloader.c
@@ -19,7 +19,8 @@
  *   USBaspLoader        2048
  */
 #ifndef BOOTLOADER_SIZE
-#warn To use bootloader_jump() you need to define BOOTLOADER_SIZE in config.h.
+#warning To use bootloader_jump() you need to define BOOTLOADER_SIZE in config.h.
+#define BOOTLOADER_SIZE     4096
 #endif
 
 #define FLASH_SIZE          (FLASHEND + 1L)