diff --git a/source/filesys/fsinit.c b/source/filesys/fsinit.c
index a49296d..b710d0b 100644
--- a/source/filesys/fsinit.c
+++ b/source/filesys/fsinit.c
@@ -34,13 +34,21 @@ bool InitExtFS() {
 }
 
 bool InitImgFS(const char* path) {
+    // find drive # of the last image FAT drive
+    u32 drv_i = NORM_FS - IMGN_FS;
+    for (; drv_i < NORM_FS; drv_i++) {
+        char fsname[8];
+        snprintf(fsname, 7, "%lu:", drv_i);
+        if (!(DriveType(fsname)&DRV_IMAGE))
+            break;
+    }
     // deinit image filesystem
     DismountDriveType(DRV_IMAGE);
     // (re)mount image, done if path == NULL
     MountImage(path);
     InitVirtualImageDrive();
     // reinit image filesystem
-    for (u32 i = NORM_FS - IMGN_FS; i < NORM_FS; i++) {
+    for (u32 i = NORM_FS - IMGN_FS; i < drv_i; i++) {
         char fsname[8];
         snprintf(fsname, 7, "%lu:", i);
         fs_mounted[i] = (f_mount(fs + i, fsname, 1) == FR_OK);