diff --git a/src/sio/sio_it86x1f.c b/src/sio/sio_it86x1f.c
index d53e78050..74e79bbed 100644
--- a/src/sio/sio_it86x1f.c
+++ b/src/sio/sio_it86x1f.c
@@ -14,9 +14,10 @@
  *
  *          Copyright 2023 RichardG.
  */
+#include <inttypes.h>
 #include <stdarg.h>
-#include <stdio.h>
 #include <stdint.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <wchar.h>
@@ -805,10 +806,18 @@ it86x1f_init(UNUSED(const device_t *info))
             break;
     }
     if (i >= (sizeof(it86x1f_models) / sizeof(it86x1f_models[0]))) {
+#if (defined __amd64__ || defined _M_X64 || defined __aarch64__ || defined _M_ARM64)
+        fatal("IT86x1F: Unknown type %04" PRIX64 " selected\n", info->local);
+#else
         fatal("IT86x1F: Unknown type %04X selected\n", info->local);
+#endif
         return NULL;
     }
+#if (defined __amd64__ || defined _M_X64 || defined __aarch64__ || defined _M_ARM64)
+    it86x1f_log("IT86x1F: init(%04" PRIX64 ")\n", info->local);
+#else
     it86x1f_log("IT86x1F: init(%04X)\n", info->local);
+#endif
 
     /* Let the resource data parser figure out the ROM size. */
     dev->pnp_card = isapnp_add_card(it86x1f_models[i].pnp_rom, -1, it86x1f_models[i].pnp_config_changed, NULL, it86x1f_pnp_read_vendor_reg, it86x1f_pnp_write_vendor_reg, dev);