diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 9f6a685..f1f12fe 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -103,15 +103,18 @@ add_custom_command(
             ${CMAKE_CURRENT_BINARY_DIR}/generated/bitmapfont.table.h
             ${CMAKE_CURRENT_SOURCE_DIR}/fonts/unifont-8.0.01.hex.gz
             ${chars}
-    DEPENDS unifont2c ${chars}
+    DEPENDS unifont2c
+            ${CMAKE_CURRENT_SOURCE_DIR}/fonts/unifont-8.0.01.hex.gz
+            ${chars}
     VERBATIM)
 
 add_custom_command(
     OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/generated/vectorfont.table.h
     COMMAND $<TARGET_FILE:lff2c>
-            "${CMAKE_CURRENT_BINARY_DIR}/generated/vectorfont.table.h"
-            "${CMAKE_CURRENT_SOURCE_DIR}/fonts/unicode.lff.gz"
-    DEPENDS lff2c ${chars}
+            ${CMAKE_CURRENT_BINARY_DIR}/generated/vectorfont.table.h
+            ${CMAKE_CURRENT_SOURCE_DIR}/fonts/unicode.lff.gz
+    DEPENDS lff2c
+            ${CMAKE_CURRENT_SOURCE_DIR}/fonts/unicode.lff.gz
     VERBATIM)
 
 set(generated_HEADERS
diff --git a/src/fonts/unicode.lff.gz b/src/fonts/unicode.lff.gz
index 98153b1..dc0d3a3 100644
Binary files a/src/fonts/unicode.lff.gz and b/src/fonts/unicode.lff.gz differ
diff --git a/src/glhelper.cpp b/src/glhelper.cpp
index ce2e9f8..876bbed 100644
--- a/src/glhelper.cpp
+++ b/src/glhelper.cpp
@@ -625,7 +625,8 @@ void ssglInitializeBitmapFont()
 
 int ssglBitmapCharWidth(char32_t chr) {
     if(!CodepointProperties[chr].exists)
-        oops();
+        chr = 0xfffd; // replacement character
+
     return CodepointProperties[chr].isWide ? 2 : 1;
 }
 
@@ -633,6 +634,9 @@ void ssglBitmapCharQuad(char32_t chr, double x, double y)
 {
     int w, h;
 
+    if(!CodepointProperties[chr].exists)
+        chr = 0xfffd; // replacement character
+
     h = 16;
     if(chr >= 0xe000 && chr <= 0xefff) {
         // Special character, like a checkbox or a radio button