diff --git a/scripts/footprint/size_report b/scripts/footprint/size_report
index c24f8a666e..2c168e7c51 100755
--- a/scripts/footprint/size_report
+++ b/scripts/footprint/size_report
@@ -115,7 +115,7 @@ def match_symbol_address(symlist, die, parser, dwarfinfo):
 def get_symbols(elf, addr_ranges):
     rom_syms = dict()
     ram_syms = dict()
-    unassigned_syms = dict()
+    unassigned_syms = list()
 
     rom_addr_ranges = addr_ranges['rom']
     ram_addr_ranges = addr_ranges['ram']
@@ -147,7 +147,7 @@ def get_symbols(elf, addr_ranges):
                     found_sec = True
 
                 if not found_sec:
-                    unassigned_syms['sym_name'] = entry
+                    unassigned_syms.append(entry)
 
     ret = {'rom': rom_syms,
            'ram': ram_syms,