diff --git a/stand/efi/libefi/efihttp.c b/stand/efi/libefi/efihttp.c
--- a/stand/efi/libefi/efihttp.c
+++ b/stand/efi/libefi/efihttp.c
@@ -565,6 +565,8 @@
 
 	if (!efihttp_init_done)
 		return (ENXIO);
+	if (f->f_dev != &efihttp_dev)
+		return (EINVAL);
 	/*
 	 * If any path fails to open, try with a trailing slash in
 	 * case it's a directory.