diff --git a/inc/constants.h b/inc/constants.h
new file mode 100644
index 0000000..22c361c
--- /dev/null
+++ b/inc/constants.h
@@ -0,0 +1,18 @@
+//
+// Copyright (c) 2017 The Altra64 project contributors
+// See LICENSE file in the project root for full license information.
+//
+
+#ifndef _CONSTANTS_H_
+#define _CONSTANTS_H_
+
+#define ED64PLUS
+#define MAX_SUPPORTED_PATH_LEN 256
+
+#ifdef ED64PLUS
+#define ED64_FIRMWARE_PATH "ED64P"
+#else
+#define ED64_FIRMWARE_PATH "ED64"
+#endif
+
+#endif
diff --git a/src/main.c b/src/main.c
index 76d24c9..8f9de99 100644
--- a/src/main.c
+++ b/src/main.c
@@ -40,6 +40,7 @@
 // YAML parser
 #include <yaml.h>
 
+#include "constants.h"
 #include "debug.h"
 #include "mem.h"
 #include "chksum64.h"
@@ -49,22 +50,12 @@
 #include "menu.h"
 #include "cic.h"
 
-#define ED64PLUS
-
-#ifdef ED64PLUS
-#define ED64_FIRMWARE_PATH "ED64P"
-#else
-#define ED64_FIRMWARE_PATH "ED64"
-#endif
-
 #ifdef USE_TRUETYPE
 #define STB_TRUETYPE_IMPLEMENTATION
 #include "stb_truetype.h"
 
 #define MAX_LIST 20
 
-#define MAX_SUPPORTED_PATH_LEN 256
-
 struct glyph
 {
     int xoff;
diff --git a/src/memorypak.c b/src/memorypak.c
index 343bf92..70771c7 100644
--- a/src/memorypak.c
+++ b/src/memorypak.c
@@ -7,6 +7,7 @@
 #include <libdragon.h>
 #include <string.h>
 #include <stdio.h>
+#include "constants.h"
 #include "types.h"
 #include "mempak.h"
 #include "memorypak.h"
@@ -382,14 +383,14 @@ void view_mpk(display_context_t disp)
 //old function to dump a mempak to a file
 void mpk_to_file(display_context_t disp, char *mpk_filename, int quick)
 {
-    u8 buff[64];
+    u8 buff[MAX_SUPPORTED_PATH_LEN];
     u8 v = 0;
     u8 ok = 0;
 
     if (quick)
-        sprintf(buff, "%s%s", mempak_path, mpk_filename);
+        sprintf(buff, "/"ED64_FIRMWARE_PATH"/%s/%s", mempak_path, mpk_filename);
     else
-        sprintf(buff, "%s%s.MPK", mempak_path, mpk_filename);
+        sprintf(buff, "/"ED64_FIRMWARE_PATH"/%s/%s.MPK", mempak_path, mpk_filename);
 
     FRESULT fr;
     FILINFO fno;
@@ -403,7 +404,7 @@ void mpk_to_file(display_context_t disp, char *mpk_filename, int quick)
         else
             while (fr == FR_OK)
             {
-                sprintf(buff, "%s%s%i.MPK", mempak_path, mpk_filename, v);
+                sprintf(buff, "/"ED64_FIRMWARE_PATH"/%s/%s.%i.MPK", mempak_path, mpk_filename, v);
 
                 fr = f_stat(buff, &fno);
                 if (fr == FR_OK)