diff --git a/backend/raster.c b/backend/raster.c
index 31dfa863..14e5d212 100644
--- a/backend/raster.c
+++ b/backend/raster.c
@@ -720,6 +720,7 @@ static int plot_raster_default(struct zint_symbol *symbol, int rotate_angle, int
     unsigned char* local_text = (unsigned char*) _alloca(ustrlen(symbol->text) + 1);
 #endif
 
+    memset(local_text, 0, ustrlen(symbol->text) + 1);
     if (symbol->show_hrt != 0) {
         /* Copy text from symbol */
         to_latin1(symbol->text, local_text);
@@ -734,8 +735,8 @@ static int plot_raster_default(struct zint_symbol *symbol, int rotate_angle, int
                 } else {
                     local_text[i] = ' ';
                 }
-                local_text[ustrlen(symbol->text)] = '\0';
             }
+            local_text[ustrlen(symbol->text)] = '\0';
         } else {
             /* For everything else, just remove the text */
             local_text[0] = '\0';
@@ -744,7 +745,6 @@ static int plot_raster_default(struct zint_symbol *symbol, int rotate_angle, int
 
     textdone = 0;
     main_width = symbol->width;
-    strcpy(addon, "");
     comp_offset = 0;
     addon_text_posn = 0.0;
     row_height = 0;
diff --git a/backend/tests/test_raster.c b/backend/tests/test_raster.c
index 692cf622..66d1f6a2 100644
--- a/backend/tests/test_raster.c
+++ b/backend/tests/test_raster.c
@@ -38,6 +38,7 @@ static void test_chk_extendable(void)
     int ret;
     struct item {
         int symbology;
+        int show_hrt;
         unsigned char* data;
         int ret;
 
@@ -51,9 +52,10 @@ static void test_chk_extendable(void)
     };
     // s/\/\*[ 0-9]*\*\//\=printf("\/*%2d*\/", line(".") - line("'<"))
     struct item data[] = {
-        /* 0*/ { BARCODE_EANX_CHK, "1234567890128+12", 0, 50, 1, 124, 288, 118, 5, 224 },
-        /* 1*/ { BARCODE_UPCA_CHK, "12345678905+12345", 0, 50, 1, 151, 342, 118, 5, 258 },
-        /* 2*/ { BARCODE_UPCE_CHK, "12345670+12", 0, 50, 1, 80, 200, 118, 5, 147 },
+        /* 0*/ { BARCODE_EANX_CHK, -1, "1234567890128+12", 0, 50, 1, 124, 288, 118, 5, 224 },
+        /* 1*/ { BARCODE_UPCA_CHK, -1, "12345678905+12345", 0, 50, 1, 151, 342, 118, 5, 258 },
+        /* 2*/ { BARCODE_UPCE_CHK, -1, "12345670+12", 0, 50, 1, 80, 200, 118, 5, 147 },
+        /* 3*/ { BARCODE_UPCE_CHK, 0, "12345670+12", 0, 50, 1, 80, 200, 118, 5, 147 },
     };
     int data_size = sizeof(data) / sizeof(struct item);
 
@@ -63,6 +65,9 @@ static void test_chk_extendable(void)
         assert_nonnull(symbol, "Symbol not created\n");
 
         symbol->symbology = data[i].symbology;
+        if (data[i].show_hrt != -1) {
+            symbol->show_hrt = data[i].show_hrt;
+        }
         int length = strlen(data[i].data);
 
         ret = ZBarcode_Encode_and_Buffer(symbol, data[i].data, length, 0);
@@ -84,7 +89,11 @@ static void test_chk_extendable(void)
                 break;
             }
         }
-        assert_nonzero(addon_text_bits_set, "i:%d (%d) addon_text_bits_set zero\n", i, data[i].symbology);
+        if (symbol->show_hrt) {
+            assert_nonzero(addon_text_bits_set, "i:%d (%d) addon_text_bits_set zero\n", i, data[i].symbology);
+        } else {
+            assert_zero(addon_text_bits_set, "i:%d (%d) addon_text_bits_set non-zero\n", i, data[i].symbology);
+        }
 
         ZBarcode_Delete(symbol);
     }