diff --git a/plugins/router/example-graphs/freebox_adsl_errors-day.png b/plugins/router/example-graphs/freebox_adsl_errors-day.png
index 0d6f4943..d823874b 100644
Binary files a/plugins/router/example-graphs/freebox_adsl_errors-day.png and b/plugins/router/example-graphs/freebox_adsl_errors-day.png differ
diff --git a/plugins/router/freebox b/plugins/router/freebox
index 86e6d90a..8d395b1a 100755
--- a/plugins/router/freebox
+++ b/plugins/router/freebox
@@ -274,18 +274,30 @@ graph_config() {
 			echo 'graph_order fec_down fec crc_down crc hec_down hec'
 
 			echo 'fec_down.label FEC down'
+			echo 'fec_down.type DERIVE'
+			echo 'fec_down.min 0'
 			echo 'fec_down.graph no'
 			echo 'fec.label FEC'
+			echo 'fec.type DERIVE'
+			echo 'fec.min 0'
 			echo 'fec.negative fec_down'
 
 			echo 'crc_down.label CRC down'
+			echo 'crc_down.type DERIVE'
+			echo 'crc_down.min 0'
 			echo 'crc_down.graph no'
 			echo 'crc.label CRC'
+			echo 'crc.type DERIVE'
+			echo 'crc.min 0'
 			echo 'crc.negative crc_down'
 
 			echo 'hec_down.label HEC down'
+			echo 'hec_down.type DERIVE'
+			echo 'hec_down.min 0'
 			echo 'hec_down.graph no'
 			echo 'hec.label HEC'
+			echo 'hec.type DERIVE'
+			echo 'hec.min 0'
 			echo 'hec.negative hec_down'
 			;;
 		.traffic)