diff --git a/block.c b/block.c
index e71a771..0aaec3b 100644
--- a/block.c
+++ b/block.c
@@ -288,24 +288,31 @@
     char protocol[128];
     int len;
     const char *p;
-    int is_drive;
 
     /* TODO Drivers without bdrv_file_open must be specified explicitly */
 
-#ifdef _WIN32
-    is_drive = is_windows_drive(filename) ||
-        is_windows_drive_prefix(filename);
-#else
-    is_drive = 0;
-#endif
-    p = strchr(filename, ':');
-    if (!p || is_drive) {
-        drv1 = find_hdev_driver(filename);
-        if (!drv1) {
-            drv1 = bdrv_find_format("file");
-        }
+    /*
+     * XXX(hch): we really should not let host device detection
+     * override an explicit protocol specification, but moving this
+     * later breaks access to device names with colons in them.
+     * Thanks to the brain-dead persistent naming schemes on udev-
+     * based Linux systems those actually are quite common.
+     */
+    drv1 = find_hdev_driver(filename);
+    if (drv1) {
         return drv1;
     }
+
+#ifdef _WIN32
+     if (is_windows_drive(filename) ||
+         is_windows_drive_prefix(filename))
+         return bdrv_find_format("file");
+#endif
+
+    p = strchr(filename, ':');
+    if (!p) {
+        return bdrv_find_format("file");
+    }
     len = p - filename;
     if (len > sizeof(protocol) - 1)
         len = sizeof(protocol) - 1;