diff --git a/firmware/system.c b/firmware/system.c
index f9dcadd..8cef29c 100644
--- a/firmware/system.c
+++ b/firmware/system.c
@@ -10,6 +10,7 @@
 #include <spiflash.h>
 
 #include <espressif/user_interface.h>
+#include <esp/uart.h>
 #include <espressif/esp_system.h>
 #include <rboot/rboot.h>
 #include <rboot-ota/rboot-api.h>
@@ -48,6 +49,20 @@ void system_init_config() {
     }
 }
 
+int fputc(int ch, FILE *f)
+{
+    uart_putc(0, '0');
+    uart_putc(0, ch);
+    return ch;
+}
+
+int	puts (const char *str)
+{
+    char c;
+    while((c=*str++))fputc(c,0);
+    return str;
+}
+
 #define MAX_IMAGE_SIZE 0x100000
 
 struct {
diff --git a/firmware/web.cpp b/firmware/web.cpp
index 6176a43..9528377 100644
--- a/firmware/web.cpp
+++ b/firmware/web.cpp
@@ -303,4 +303,14 @@ extern "C" void httpd_task(void *pvParameters) {
     httpd_init();
 
     vTaskDelete(nullptr);
-}
\ No newline at end of file
+}
+
+#include <stdio.h>
+#include <espressif/esp_common.h>
+
+void test(){
+
+    printf("foo\n");
+    printf("Warning: WiFi config, sysparam not initialized\n");
+    printf("SDK version: %s\n", sdk_system_get_sdk_version());
+};
\ No newline at end of file