diff --git a/applications/serial_lte_modem/overlay-ppp.conf b/applications/serial_lte_modem/overlay-ppp.conf
index 5c027f0b2539..8e01582a2228 100644
--- a/applications/serial_lte_modem/overlay-ppp.conf
+++ b/applications/serial_lte_modem/overlay-ppp.conf
@@ -25,6 +25,7 @@ CONFIG_MODEM_MODULES=y
 CONFIG_MODEM_PPP=y
 CONFIG_MODEM_BACKEND_UART=y
 CONFIG_MODEM_BACKEND_UART_ASYNC_TRANSMIT_TIMEOUT_MS=1000
+CONFIG_MODEM_BACKEND_UART_ASYNC_HWFC=y
 
 # L2 protocol
 CONFIG_NET_L2_PPP_MGMT=y
@@ -46,6 +47,7 @@ CONFIG_NET_BUF_RX_COUNT=88
 CONFIG_NET_PKT_TX_COUNT=44
 CONFIG_NET_BUF_TX_COUNT=88
 CONFIG_NET_TC_RX_COUNT=0
+CONFIG_NET_CONN_PACKET_CLONE_TIMEOUT=1000
 
 # debug options
 #CONFIG_LOG_PROCESS_THREAD_STACK_SIZE=4096