Moved the sanity checks to the correct place.

src/disk/mo.c

@@ -2147,14 +2147,14 @@ mo_hard_reset(void)
 
             dev = (mo_t *) mo_drives[c].priv;
 
+            if (dev->tf == NULL)
+                continue;
+
             dev->id  = c;
             dev->drv = &mo_drives[c];
 
             mo_init(dev);
 
-            if (dev->tf == NULL)
-                continue;
-
             if (strlen(mo_drives[c].image_path))
                 mo_load(dev, mo_drives[c].image_path);
 

src/disk/zip.c

@@ -2386,14 +2386,14 @@ zip_hard_reset(void)
 
             dev = (zip_t *) zip_drives[c].priv;
 
+            if (dev->tf == NULL)
+                continue;
+
             dev->id  = c;
             dev->drv = &zip_drives[c];
 
             zip_init(dev);
 
-            if (dev->tf == NULL)
-                continue;
-
             if (strlen(zip_drives[c].image_path))
                 zip_load(dev, zip_drives[c].image_path);