diff --git a/cpu/esp8266/tools.c b/cpu/esp8266/tools.c
index 230621a091..bb50088d2d 100644
--- a/cpu/esp8266/tools.c
+++ b/cpu/esp8266/tools.c
@@ -47,10 +47,10 @@ void esp_hexdump (const void* addr, uint32_t num, char width, uint8_t per_line)
             printf ("%08x: ", (uint32_t)((uint8_t*)addr+count*size));
         }
         switch (width) {
-            case 'b': printf("%02" PRIx8, addr8[count++]); break;
-            case 'h': printf("%04" PRIx16, addr16[count++]); break;
-            case 'w': printf("%08" PRIx32, addr32[count++]); break;
-            case 'g': printf("%016" PRIx64, addr64[count++]); break;
+            case 'b': printf("%02" PRIx8 " ", addr8[count++]); break;
+            case 'h': printf("%04" PRIx16 " ", addr16[count++]); break;
+            case 'w': printf("%08" PRIx32 " ", addr32[count++]); break;
+            case 'g': printf("%016" PRIx64 " ", addr64[count++]); break;
 
             default : printf("."); count++; break;
         }