diff --git a/micropython/extmod/modtrezorui/font_roboto_bold_20.h b/micropython/extmod/modtrezorui/font_roboto_bold_20.h
index 2afefd29..74055e69 100644
--- a/micropython/extmod/modtrezorui/font_roboto_bold_20.h
+++ b/micropython/extmod/modtrezorui/font_roboto_bold_20.h
@@ -1,3 +1,3 @@
 #include <stdint.h>
 
-const uint8_t * const Font_Roboto_Bold_20[126 + 1 - 32];
+extern const uint8_t * const Font_Roboto_Bold_20[126 + 1 - 32];
diff --git a/micropython/extmod/modtrezorui/font_roboto_regular_20.h b/micropython/extmod/modtrezorui/font_roboto_regular_20.h
index 27bee6ca..2f202bdf 100644
--- a/micropython/extmod/modtrezorui/font_roboto_regular_20.h
+++ b/micropython/extmod/modtrezorui/font_roboto_regular_20.h
@@ -1,3 +1,3 @@
 #include <stdint.h>
 
-const uint8_t * const Font_Roboto_Regular_20[126 + 1 - 32];
+extern const uint8_t * const Font_Roboto_Regular_20[126 + 1 - 32];
diff --git a/micropython/extmod/modtrezorui/font_robotomono_regular_20.h b/micropython/extmod/modtrezorui/font_robotomono_regular_20.h
index af28ef1a..dc1fcbae 100644
--- a/micropython/extmod/modtrezorui/font_robotomono_regular_20.h
+++ b/micropython/extmod/modtrezorui/font_robotomono_regular_20.h
@@ -1,3 +1,3 @@
 #include <stdint.h>
 
-const uint8_t * const Font_RobotoMono_Regular_20[126 + 1 - 32];
+extern const uint8_t * const Font_RobotoMono_Regular_20[126 + 1 - 32];
diff --git a/tools/ttf2c b/tools/ttf2c
index 2cfb8cdc..e49b57d0 100755
--- a/tools/ttf2c
+++ b/tools/ttf2c
@@ -13,7 +13,7 @@ def process_face(name, style, size):
     fontname = '%s_%s_%d' % (name.lower(), style.lower(), size)
     with open('font_%s.h' % fontname, 'wt') as f:
         f.write('#include <stdint.h>\n\n')
-        f.write('const uint8_t * const Font_%s_%s_%d[%d + 1 - %d];\n' % (name, style, size, MAX_GLYPH, MIN_GLYPH))
+        f.write('extern const uint8_t * const Font_%s_%s_%d[%d + 1 - %d];\n' % (name, style, size, MAX_GLYPH, MIN_GLYPH))
     with open('font_%s.c' % fontname, 'wt') as f:
         f.write('#include "font_%s.h"\n\n' % fontname)
         f.write('// first two bytes are width and height of the glyph\n')