diff --git a/src/lv_misc/lv_bidi.c b/src/lv_misc/lv_bidi.c
index 0f1153b52..bde752071 100644
--- a/src/lv_misc/lv_bidi.c
+++ b/src/lv_misc/lv_bidi.c
@@ -232,7 +232,7 @@ void lv_bidi_process_paragraph(const char * str_in, char * str_out, uint32_t len
 
     /*Get and process the runs*/
 
-    while(rd < len) {
+    while(rd < len && str_in[rd]) {
         run_dir = get_next_run(&str_in[rd], base_dir, len - rd, &run_len, &pos_conv_run_len);
 
         if(base_dir == LV_BIDI_DIR_LTR) {
diff --git a/src/lv_objx/lv_label.c b/src/lv_objx/lv_label.c
index 29fae15b0..bd99c10c8 100644
--- a/src/lv_objx/lv_label.c
+++ b/src/lv_objx/lv_label.c
@@ -626,7 +626,7 @@ void lv_label_get_letter_pos(const lv_obj_t * label, uint16_t char_id, lv_point_
         }
     }
 
-    char *bidi_txt;
+    const char *bidi_txt;
     uint16_t visual_byte_pos;
 #if LV_USE_BIDI
     /*Handle Bidi*/
@@ -638,7 +638,9 @@ void lv_label_get_letter_pos(const lv_obj_t * label, uint16_t char_id, lv_point_
         uint16_t line_char_id = lv_txt_encoded_get_char_id(&txt[line_start], byte_id - line_start);
 
         bool is_rtl;
-        uint16_t visual_char_pos = lv_bidi_get_visual_pos(&txt[line_start], &bidi_txt, new_line_start - line_start, lv_obj_get_base_dir(label), line_char_id, &is_rtl);
+        char *mutable_bidi_txt;
+        uint16_t visual_char_pos = lv_bidi_get_visual_pos(&txt[line_start], &mutable_bidi_txt, new_line_start - line_start, lv_obj_get_base_dir(label), line_char_id, &is_rtl);
+        bidi_txt = mutable_bidi_txt;
         if (is_rtl) visual_char_pos++;
         visual_byte_pos = lv_txt_encoded_get_byte_id(bidi_txt, visual_char_pos);
     }