diff --git a/tools/testing/selftests/drivers/net/ocelot/psfp.sh b/tools/testing/selftests/drivers/net/ocelot/psfp.sh
index 5a5cee92c665..bed748dde4b0 100755
--- a/tools/testing/selftests/drivers/net/ocelot/psfp.sh
+++ b/tools/testing/selftests/drivers/net/ocelot/psfp.sh
@@ -181,7 +181,7 @@ setup_prepare()
 
 	# Set up swp1 as a master PHC for h1, synchronized to the local
 	# CLOCK_REALTIME.
-	phc2sys_start ${swp1} ${UDS_ADDRESS_SWP1}
+	phc2sys_start ${UDS_ADDRESS_SWP1}
 
 	# Assumption true for LS1028A: h1 and h2 use the same PHC. So by
 	# synchronizing h1 to swp1 via PTP, h2 is also implicitly synchronized
diff --git a/tools/testing/selftests/net/forwarding/tsn_lib.sh b/tools/testing/selftests/net/forwarding/tsn_lib.sh
index 20c2b411ba36..b91bcd8008a9 100644
--- a/tools/testing/selftests/net/forwarding/tsn_lib.sh
+++ b/tools/testing/selftests/net/forwarding/tsn_lib.sh
@@ -22,8 +22,7 @@ fi
 
 phc2sys_start()
 {
-	local if_name=$1
-	local uds_address=$2
+	local uds_address=$1
 	local extra_args=""
 
 	if ! [ -z "${uds_address}" ]; then
@@ -33,9 +32,7 @@ phc2sys_start()
 	phc2sys_log="$(mktemp)"
 
 	chrt -f 10 phc2sys -m \
-		-c ${if_name} \
-		-s CLOCK_REALTIME \
-		-O ${UTC_TAI_OFFSET} \
+		-a -rr \
 		--step_threshold 0.00002 \
 		--first_step_threshold 0.00002 \
 		${extra_args} \