diff --git a/IoT_Basic_Kit_Tester/images.h b/IoT_Basic_Kit_Tester/images.h
index 3068e5b..9d67550 100644
--- a/IoT_Basic_Kit_Tester/images.h
+++ b/IoT_Basic_Kit_Tester/images.h
@@ -1,6 +1,6 @@
 #define Bluino_logo_width 120
 #define Bluino_logo_height 33
-static char Bluino_logo_bits[] = {
+static uint8_t Bluino_logo_bits[] = {
   0xFE, 0xFF, 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
   0x00, 0x00, 0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0x01, 0x00, 0x00, 0x00, 0x00, 
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0x81, 0x7F,