diff --git a/src/asm_matcher.ml b/src/asm_matcher.ml
index ed01523..e029f71 100644
--- a/src/asm_matcher.ml
+++ b/src/asm_matcher.ml
@@ -8,6 +8,8 @@ module BlockidMap = Map.Make(struct
   end)
 
 type asm_block_info = {
+  asm_bi_dwarfhead : Dwarf.line_number_header ; (* FIXME overkill to carry
+                                                   around? *)
   asm_bi_dwarfline : Dwarf.line_number_registers ;
   asm_bi_blockid : blockid_t ;
 }
@@ -20,9 +22,24 @@ let fresh_blockid =
     incr next_id ;
     out
 
+(** Gets the file path for a given file id and header data *)
+let extract_file_name file_id files_list =
+  let file_data = List.nth files_list (file_id - 1) in
+  file_data.Dwarf.lnfe_path
+  |> List.to_seq
+  |> String.of_seq
+
+
+(** Gets the file path for the given blk, instead of its id *)
+let get_file_name blk = Dwarf.(
+    let file_id = blk.asm_bi_dwarfline.lnr_file
+                  |> Z.to_int in
+    extract_file_name file_id blk.asm_bi_dwarfhead.lnh_file_names
+  )
+
 (** Compares two block infos wrt. class equivalence *)
 let asm_bi_compare blk1 blk2 =
-  let select_file blk = Dwarf.(blk.asm_bi_dwarfline.lnr_file) in
+  let select_file blk = get_file_name blk in
   let select_line blk = Dwarf.(blk.asm_bi_dwarfline.lnr_line) in
   let select_col blk = Dwarf.(blk.asm_bi_dwarfline.lnr_column) in
 
@@ -81,8 +98,9 @@ let add_block_bi state blockinfo =
     argument and generates a fresh id by itself.
     WARNING! Do not mix automatically and manually generated ids.
 *)
-let add_block state lnr =
+let add_block state lnh lnr =
   add_block_bi state {
+    asm_bi_dwarfhead = lnh ;
     asm_bi_dwarfline = lnr ;
     asm_bi_blockid = fresh_blockid ()
   }
diff --git a/src/elf_arrows.ml b/src/elf_arrows.ml
index 585a0bc..b28dbaa 100644
--- a/src/elf_arrows.ml
+++ b/src/elf_arrows.ml
@@ -45,7 +45,8 @@ let add_line_boxes render_data matcher_data dwarf_lines =
     do_fold base lst
   in
 
-  List.fold_left (fun (cur_render_data, cur_matcher_data) (_, reg_list) ->
+  List.fold_left (fun (cur_render_data, cur_matcher_data)
+                   (reg_header, reg_list) ->
       fold_ahead (fun (cur_render_data, cur_matcher_data) cur_reg reg_ahead ->
           let box_start = Z.to_int @@ cur_reg.Dwarf.lnr_address in
           let box_end = Z.to_int @@ reg_ahead.Dwarf.lnr_address in
@@ -54,11 +55,16 @@ let add_line_boxes render_data matcher_data dwarf_lines =
            | false ->
              Format.eprintf "Add box %x -- %x@." box_start box_end ;
              let n_matcher_data, block_class_id =
-               Asm_matcher.add_block cur_matcher_data cur_reg in
+               Asm_matcher.add_block cur_matcher_data reg_header cur_reg in
+             let file_name = (
+               let file_id = cur_reg.lnr_file
+                             |> Z.to_int in
+               Asm_matcher.extract_file_name file_id reg_header.lnh_file_names
+             ) in
              let n_render_data, _ = Renderer.add_box_excl
                  cur_render_data (box_start, box_end)
                  Renderer.(Some {
-                     box_file = Z.to_int cur_reg.lnr_file;
+                     box_file = file_name ;
                      box_line = Z.to_int cur_reg.lnr_line;
                      box_col = Z.to_int cur_reg.lnr_column;
                      box_class_id = block_class_id;
diff --git a/src/html_renderer.ml b/src/html_renderer.ml
index 29e10ee..dfdc4d7 100644
--- a/src/html_renderer.ml
+++ b/src/html_renderer.ml
@@ -46,7 +46,7 @@ let render_prog_box annotated_prog = Jingoo.Jg_types.(Renderer.AnnotAsm.(
                      ("typ", box_string typ);
                      ("id", box_int id);
                      ("bound", box_string @@ render_addr bound);
-                     ("data", box_string @@ Format.sprintf "[%d] File %d, %d:%d"
+                     ("data", box_string @@ Format.sprintf "[%d] File %s, %d:%d"
                         data.box_class_id data.box_file data.box_line data.box_col);
                      ("box_eq", box_int data.box_class_id);
 
diff --git a/src/renderer.ml b/src/renderer.ml
index c9ecebd..758eb3b 100644
--- a/src/renderer.ml
+++ b/src/renderer.ml
@@ -8,7 +8,7 @@ module RawAsm = Asm_info.NoAnnot
 
 type addr_range_t = RawAsm.addr_t * RawAsm.addr_t
 type box_data_t = {
-  box_file : int;
+  box_file : string;
   box_line : int;
   box_col : int;
   box_class_id : int;
@@ -82,7 +82,7 @@ let add_box render_data range opt_data : render_data_t * int =
   let data = (match opt_data with
       | Some data -> data
       | None -> {
-          box_file = 0;
+          box_file = "";
           box_line = 0;
           box_col = 0;
           box_class_id = 0;