diff --git a/sys/dev/firewire/firewire.h b/sys/dev/firewire/firewire.h
index ab34748bec25..ee510e624bc3 100644
--- a/sys/dev/firewire/firewire.h
+++ b/sys/dev/firewire/firewire.h
@@ -375,7 +375,7 @@ struct fw_speed_map {
 
 struct fw_crom_buf {
 	struct fw_eui64 eui;
-	int len;
+	uint32_t len;
 	void *ptr;
 };
 
diff --git a/sys/dev/firewire/fwdev.c b/sys/dev/firewire/fwdev.c
index 60e73849fca5..23e95bb0c398 100644
--- a/sys/dev/firewire/fwdev.c
+++ b/sys/dev/firewire/fwdev.c
@@ -712,7 +712,7 @@ out:
 			else
 				len = fwdev->rommax - CSRROMOFF + 4;
 		}
-		if (crom_buf->len < len && crom_buf->len >= 0)
+		if (crom_buf->len < len)
 			len = crom_buf->len;
 		else
 			crom_buf->len = len;