diff --git a/board/solidrun/clearfog/clearfog.c b/board/solidrun/clearfog/clearfog.c
index 11d3a7f..8f3e5dc 100644
--- a/board/solidrun/clearfog/clearfog.c
+++ b/board/solidrun/clearfog/clearfog.c
@@ -63,6 +63,11 @@
 {
 	cf_read_tlv_data();
 
+	/* Apply build configuration options before runtime configuration */
+	if (IS_ENABLED(CONFIG_CLEARFOG_SFP_25GB))
+		board_serdes_map[5].serdes_speed = SERDES_SPEED_3_125_GBPS;
+
+	/* Apply runtime detection changes */
 	if (sr_product_is(&cf_tlv_data, "Clearfog GTR")) {
 		board_serdes_map[0].serdes_type = PEX0;
 		board_serdes_map[0].serdes_speed = SERDES_SPEED_5_GBPS;