diff --git a/examples/ssd1306_fps/main.c b/examples/ssd1306_fps/main.c
index 6c56331..3fcb2b0 100644
--- a/examples/ssd1306_fps/main.c
+++ b/examples/ssd1306_fps/main.c
@@ -37,6 +37,8 @@
     #define DC_PIN   4
 #endif
 
+#define DEFAULT_FONT FONT_FACE_TERMINUS_6X12_ISO8859_1
+
 /* Declare device descriptor */
 static const ssd1306_t dev = {
     .protocol = PROTOCOL,
@@ -82,8 +84,7 @@ static void ssd1306_task(void *pvParameters)
 
         ssd1306_draw_string(&dev, buffer, font, 0, 0, "Hello, esp-open-rtos!", OLED_COLOR_WHITE, OLED_COLOR_BLACK);
         sprintf(text, "FPS: %u   ", fps);
-        ssd1306_draw_string(&dev, buffer, font_builtin_fonts[FONT_FACE_TERMINUS_6X12_KOI8_R],
-            0, 40, text, OLED_COLOR_WHITE, OLED_COLOR_BLACK);
+        ssd1306_draw_string(&dev, buffer, font_builtin_fonts[DEFAULT_FONT], 0, 40, text, OLED_COLOR_WHITE, OLED_COLOR_BLACK);
 
         // generate loading icon
         ssd1306_draw_line(&dev, buffer, x0, y0, x1, y1, OLED_COLOR_BLACK);
diff --git a/extras/fonts/component.mk b/extras/fonts/component.mk
index a48eca4..b9d7ec4 100644
--- a/extras/fonts/component.mk
+++ b/extras/fonts/component.mk
@@ -18,19 +18,19 @@ fonts_CFLAGS = $(CFLAGS) \
 	-DFONTS_BITOCRA_4X7=$(FONTS_BITOCRA_4X7) \
 	-DFONTS_BITOCRA_6X11=$(FONTS_BITOCRA_6X11) \
 	-DFONTS_BITOCRA_7X13=$(FONTS_BITOCRA_7X13) \
-    -DFONTS_TERMINUS_6X12_ISO8859_1=$(FONTS_TERMINUS_6X12_ISO8859_1) \
-    -DFONTS_TERMINUS_8X14_ISO8859_1=$(FONTS_TERMINUS_8X14_ISO8859_1) \
-    -DFONTS_TERMINUS_BOLD_8X14_ISO8859_1=$(FONTS_TERMINUS_BOLD_8X14_ISO8859_1) \
-    -DFONTS_TERMINUS_10X18_ISO8859_1=$(FONTS_TERMINUS_10X18_ISO8859_1) \
-    -DFONTS_TERMINUS_BOLD_10X18_ISO8859_1=$(FONTS_TERMINUS_BOLD_10X18_ISO8859_1) \
-    -DFONTS_TERMINUS_11X22_ISO8859_1=$(FONTS_TERMINUS_11X22_ISO8859_1) \
-    -DFONTS_TERMINUS_BOLD_11X22_ISO8859_1=$(FONTS_TERMINUS_BOLD_11X22_ISO8859_1) \
-    -DFONTS_TERMINUS_12X24_ISO8859_1=$(FONTS_TERMINUS_12X24_ISO8859_1) \
-    -DFONTS_TERMINUS_BOLD_12X24_ISO8859_1=$(FONTS_TERMINUS_BOLD_12X24_ISO8859_1) \
-    -DFONTS_TERMINUS_14X28_ISO8859_1=$(FONTS_TERMINUS_14X28_ISO8859_1) \
-    -DFONTS_TERMINUS_BOLD_14X28_ISO8859_1=$(FONTS_TERMINUS_BOLD_14X28_ISO8859_1) \
-    -DFONTS_TERMINUS_16X32_ISO8859_1=$(FONTS_TERMINUS_16X32_ISO8859_1) \
-    -DFONTS_TERMINUS_BOLD_16X32_ISO8859_1=$(FONTS_TERMINUS_BOLD_16X32_ISO8859_1) \
+	-DFONTS_TERMINUS_6X12_ISO8859_1=$(FONTS_TERMINUS_6X12_ISO8859_1) \
+	-DFONTS_TERMINUS_8X14_ISO8859_1=$(FONTS_TERMINUS_8X14_ISO8859_1) \
+	-DFONTS_TERMINUS_BOLD_8X14_ISO8859_1=$(FONTS_TERMINUS_BOLD_8X14_ISO8859_1) \
+	-DFONTS_TERMINUS_10X18_ISO8859_1=$(FONTS_TERMINUS_10X18_ISO8859_1) \
+	-DFONTS_TERMINUS_BOLD_10X18_ISO8859_1=$(FONTS_TERMINUS_BOLD_10X18_ISO8859_1) \
+	-DFONTS_TERMINUS_11X22_ISO8859_1=$(FONTS_TERMINUS_11X22_ISO8859_1) \
+	-DFONTS_TERMINUS_BOLD_11X22_ISO8859_1=$(FONTS_TERMINUS_BOLD_11X22_ISO8859_1) \
+	-DFONTS_TERMINUS_12X24_ISO8859_1=$(FONTS_TERMINUS_12X24_ISO8859_1) \
+	-DFONTS_TERMINUS_BOLD_12X24_ISO8859_1=$(FONTS_TERMINUS_BOLD_12X24_ISO8859_1) \
+	-DFONTS_TERMINUS_14X28_ISO8859_1=$(FONTS_TERMINUS_14X28_ISO8859_1) \
+	-DFONTS_TERMINUS_BOLD_14X28_ISO8859_1=$(FONTS_TERMINUS_BOLD_14X28_ISO8859_1) \
+	-DFONTS_TERMINUS_16X32_ISO8859_1=$(FONTS_TERMINUS_16X32_ISO8859_1) \
+	-DFONTS_TERMINUS_BOLD_16X32_ISO8859_1=$(FONTS_TERMINUS_BOLD_16X32_ISO8859_1) \
 	-DFONTS_TERMINUS_6X12_KOI8_R=$(FONTS_TERMINUS_6X12_KOI8_R) \
 	-DFONTS_TERMINUS_8X14_KOI8_R=$(FONTS_TERMINUS_8X14_KOI8_R) \
 	-DFONTS_TERMINUS_BOLD_8X14_KOI8_R=$(FONTS_TERMINUS_BOLD_8X14_KOI8_R) \
diff --git a/extras/fonts/fonts.c b/extras/fonts/fonts.c
index 86a35cc..fb6bcc3 100644
--- a/extras/fonts/fonts.c
+++ b/extras/fonts/fonts.c
@@ -246,7 +246,7 @@ uint16_t font_measure_string(const font_info_t *fnt, const char *s)
     if (!s || !fnt) return 0;
 
     uint16_t res = 0;
-    while (s)
+    while (*s)
     {
         const font_char_desc_t *d = font_get_char_desc(fnt, *s);
         if (d)