diff --git a/src/main.cpp b/src/main.cpp
index 65d4b7a..cf7bd4a 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -78,11 +78,15 @@ int version_func(CommandRouter *cmd, int argc, const char **argv) {
 int serialnumber_func(CommandRouter *cmd, int argc, const char **argv) {
   (void)argc;
   (void)argv;
-  int i;
+  uint8_t i;
   // https://github.com/PaulStoffregen/cores/pull/722
-  for (i=0; i < 10; i++) {
+#pragma GCC diagnostic push
+  // https://gcc.gnu.org/onlinedocs/gcc/Diagnostic-Pragmas.html
+#pragma GCC diagnostic ignored "-Warray-bounds"
+  for (i=0; i < (usb_string_serial_number.bLength - 2) / sizeof(uint16_t); i++) {
     cmd->buffer[i] = (char)usb_string_serial_number.wString[i];
   }
+#pragma GCC diagnostic pop
   cmd->buffer[i] = '\0';
   return 0;
 }