diff --git a/src/dbg.cpp b/src/dbg.cpp
index 822d780..34a6ca9 100644
--- a/src/dbg.cpp
+++ b/src/dbg.cpp
@@ -1,6 +1,9 @@
 #include <dbg.h>
 #include <stdint.h>
 
+/* WARNING: use of static variable is not thread safe!! */
+static char string[32];
+
 /* Never call this function directly: always use the printk,
  * which disables and reenables interrupts */
 extern "C" int c_printk(const char* msg) {
@@ -18,8 +21,6 @@ extern "C" int printkl(const char* msg) {
     return 0;
 }
 
-static char string[11];
-/* TODO: WARNING: this is not thread safe!! */
 extern "C" const char* itoa(uint32_t n) {
     string[10] = '\0';
     string[0] = '0'; string[1] = 'x';