diff --git a/tests/zephyr/drivers/uart/uart_elementary/boards/nrf54l09pdk_nrf54l09_cpuflpr.overlay b/tests/zephyr/drivers/uart/uart_elementary/boards/nrf54l09pdk_nrf54l09_cpuflpr.overlay
new file mode 100644
index 000000000000..c585e92ec496
--- /dev/null
+++ b/tests/zephyr/drivers/uart/uart_elementary/boards/nrf54l09pdk_nrf54l09_cpuflpr.overlay
@@ -0,0 +1,29 @@
+&pinctrl {
+	uart21_default: uart21_default {
+		group1 {
+			psels = <NRF_PSEL(UART_TX, 1, 10)>,
+				<NRF_PSEL(UART_RX, 1, 11)>,
+				<NRF_PSEL(UART_RTS, 1, 8)>,
+				<NRF_PSEL(UART_CTS, 1, 9)>;
+		};
+	};
+
+	uart21_sleep: uart21_sleep {
+		group1 {
+			psels = <NRF_PSEL(UART_TX, 1, 10)>,
+				<NRF_PSEL(UART_RX, 1, 11)>,
+				<NRF_PSEL(UART_RTS, 1, 8)>,
+				<NRF_PSEL(UART_CTS, 1, 9)>;
+			low-power-enable;
+		};
+	};
+};
+
+dut: &uart21 {
+	status = "okay";
+	current-speed = <115200>;
+	pinctrl-0 = <&uart21_default>;
+	pinctrl-1 = <&uart21_sleep>;
+	pinctrl-names = "default", "sleep";
+	hw-flow-control;
+};
diff --git a/tests/zephyr/drivers/uart/uart_elementary/boards/nrf54l09pdk_nrf54l09_cpuapp_dual_uart.overlay b/tests/zephyr/drivers/uart/uart_elementary/boards/nrf54l09pdk_nrf54l09_dual_uart.overlay
similarity index 100%
rename from tests/zephyr/drivers/uart/uart_elementary/boards/nrf54l09pdk_nrf54l09_cpuapp_dual_uart.overlay
rename to tests/zephyr/drivers/uart/uart_elementary/boards/nrf54l09pdk_nrf54l09_dual_uart.overlay
diff --git a/tests/zephyr/drivers/uart/uart_elementary/boards/nrf54l20pdk_nrf54l20_cpuflpr.overlay b/tests/zephyr/drivers/uart/uart_elementary/boards/nrf54l20pdk_nrf54l20_cpuflpr.overlay
new file mode 100644
index 000000000000..c585e92ec496
--- /dev/null
+++ b/tests/zephyr/drivers/uart/uart_elementary/boards/nrf54l20pdk_nrf54l20_cpuflpr.overlay
@@ -0,0 +1,29 @@
+&pinctrl {
+	uart21_default: uart21_default {
+		group1 {
+			psels = <NRF_PSEL(UART_TX, 1, 10)>,
+				<NRF_PSEL(UART_RX, 1, 11)>,
+				<NRF_PSEL(UART_RTS, 1, 8)>,
+				<NRF_PSEL(UART_CTS, 1, 9)>;
+		};
+	};
+
+	uart21_sleep: uart21_sleep {
+		group1 {
+			psels = <NRF_PSEL(UART_TX, 1, 10)>,
+				<NRF_PSEL(UART_RX, 1, 11)>,
+				<NRF_PSEL(UART_RTS, 1, 8)>,
+				<NRF_PSEL(UART_CTS, 1, 9)>;
+			low-power-enable;
+		};
+	};
+};
+
+dut: &uart21 {
+	status = "okay";
+	current-speed = <115200>;
+	pinctrl-0 = <&uart21_default>;
+	pinctrl-1 = <&uart21_sleep>;
+	pinctrl-names = "default", "sleep";
+	hw-flow-control;
+};
diff --git a/tests/zephyr/drivers/uart/uart_elementary/boards/nrf54l20pdk_nrf54l20_dual_uart.overlay b/tests/zephyr/drivers/uart/uart_elementary/boards/nrf54l20pdk_nrf54l20_dual_uart.overlay
new file mode 100644
index 000000000000..1f817192a86c
--- /dev/null
+++ b/tests/zephyr/drivers/uart/uart_elementary/boards/nrf54l20pdk_nrf54l20_dual_uart.overlay
@@ -0,0 +1,49 @@
+&pinctrl {
+	uart21_default: uart21_default {
+		group1 {
+			psels = <NRF_PSEL(UART_TX, 1, 10)>,
+				<NRF_PSEL(UART_RX, 1, 8)>;
+				bias-pull-up;
+		};
+	};
+
+	uart21_sleep: uart21_sleep {
+		group1 {
+			psels = <NRF_PSEL(UART_TX, 1, 10)>,
+				<NRF_PSEL(UART_RX, 1, 8)>;
+			low-power-enable;
+		};
+	};
+
+	uart22_default: uart22_default {
+		group1 {
+			psels = <NRF_PSEL(UART_TX, 1, 9)>,
+				<NRF_PSEL(UART_RX, 1, 11)>;
+				bias-pull-up;
+		};
+	};
+
+	uart22_sleep: uart22_sleep {
+		group1 {
+			psels = <NRF_PSEL(UART_TX, 1, 9)>,
+				<NRF_PSEL(UART_RX, 1, 11)>;
+			low-power-enable;
+		};
+	};
+};
+
+dut: &uart21 {
+	status = "okay";
+	current-speed = <115200>;
+	pinctrl-0 = <&uart21_default>;
+	pinctrl-1 = <&uart21_sleep>;
+	pinctrl-names = "default", "sleep";
+};
+
+dut_aux: &uart22 {
+	status = "okay";
+	current-speed = <115200>;
+	pinctrl-0 = <&uart22_default>;
+	pinctrl-1 = <&uart22_sleep>;
+	pinctrl-names = "default", "sleep";
+};
diff --git a/tests/zephyr/drivers/uart/uart_elementary/testcase.yaml b/tests/zephyr/drivers/uart/uart_elementary/testcase.yaml
index 9a0ec7e20596..b42a5a805573 100644
--- a/tests/zephyr/drivers/uart/uart_elementary/testcase.yaml
+++ b/tests/zephyr/drivers/uart/uart_elementary/testcase.yaml
@@ -12,14 +12,17 @@ tests:
     filter: CONFIG_SERIAL_SUPPORT_INTERRUPT
     platform_allow:
       - nrf54l09pdk/nrf54l09/cpuapp
+      - nrf54l09pdk/nrf54l09/cpuflpr
+      - nrf54l20pdk/nrf54l20/cpuflpr
     integration_platforms:
       - nrf54l09pdk/nrf54l09/cpuapp
   nrf.extended.drivers.uart.uart_elementary_dual_l09:
     filter: CONFIG_SERIAL_SUPPORT_INTERRUPT
     platform_allow:
       - nrf54l09pdk/nrf54l09/cpuapp
+      - nrf54l09pdk/nrf54l09/cpuflpr
     extra_args:
-      - DTC_OVERLAY_FILE="boards/nrf54l09pdk_nrf54l09_cpuapp_dual_uart.overlay"
+      - DTC_OVERLAY_FILE="boards/nrf54l09pdk_nrf54l09_dual_uart.overlay"
     extra_configs:
       - CONFIG_DUAL_UART_TEST=y
     tags:
@@ -28,10 +31,28 @@ tests:
     filter: CONFIG_SERIAL_SUPPORT_INTERRUPT
     platform_allow:
       - nrf54l09pdk/nrf54l09/cpuapp
+      - nrf54l09pdk/nrf54l09/cpuflpr
     extra_args:
-      - DTC_OVERLAY_FILE="boards/nrf54l09pdk_nrf54l09_cpuapp_dual_uart.overlay"
+      - DTC_OVERLAY_FILE="boards/nrf54l09pdk_nrf54l09_dual_uart.overlay"
     extra_configs:
       - CONFIG_DUAL_UART_TEST=y
       - CONFIG_SETUP_MISMATCH_TEST=y
     tags:
       - nrf54l09-switch-uart
+  nrf.extended.drivers.uart.uart_elementary_dual_l20:
+    filter: CONFIG_SERIAL_SUPPORT_INTERRUPT
+    platform_allow:
+      - nrf54l20pdk/nrf54l20/cpuflpr
+    extra_args:
+      - DTC_OVERLAY_FILE="boards/nrf54l20pdk_nrf54l20_dual_uart.overlay"
+    extra_configs:
+      - CONFIG_DUAL_UART_TEST=y
+  nrf.extended.drivers.uart.uart_elementary_dual_setup_mismatch_l20:
+    filter: CONFIG_SERIAL_SUPPORT_INTERRUPT
+    platform_allow:
+      - nrf54l20pdk/nrf54l20/cpuflpr
+    extra_args:
+      - DTC_OVERLAY_FILE="boards/nrf54l20pdk_nrf54l20_dual_uart.overlay"
+    extra_configs:
+      - CONFIG_DUAL_UART_TEST=y
+      - CONFIG_SETUP_MISMATCH_TEST=y