diff --git a/components/services/gpio_exp.c b/components/services/gpio_exp.c
index cada03b2..cf7bf62c 100644
--- a/components/services/gpio_exp.c
+++ b/components/services/gpio_exp.c
@@ -102,8 +102,8 @@ struct gpio_exp_s *gpio_exp_get_expander(int gpio) {
 struct gpio_exp_s* gpio_exp_create(const gpio_exp_config_t *config) {
 	struct gpio_exp_s *expander = expanders + n_expanders;
 	
-	if (config->base < GPIO_EXP_BASE_MIN || n_expanders == sizeof(expanders)/sizeof(struct gpio_exp_s)) {
-		ESP_LOGE(TAG, "Base %d GPIO must be > %d for %s or too many expanders %d", config->base, GPIO_EXP_BASE_MIN, config->model, n_expanders);
+	if (config->base < GPIO_NUM_MAX || n_expanders == sizeof(expanders)/sizeof(struct gpio_exp_s)) {
+		ESP_LOGE(TAG, "Base %d GPIO must be at least %d for %s or too many expanders %d", config->base, GPIO_NUM_MAX, config->model, n_expanders);
 		return NULL;
 	}
 
@@ -305,22 +305,22 @@ void gpio_exp_enumerate(gpio_exp_enumerator enumerator, struct gpio_exp_s *expan
  * Wrapper function
  */
 esp_err_t gpio_set_pull_mode_u(int gpio, gpio_pull_mode_t mode) {
-	if (gpio < GPIO_EXP_BASE_MIN) return gpio_set_pull_mode(gpio, mode);
+	if (gpio < GPIO_NUM_MAX) return gpio_set_pull_mode(gpio, mode);
 	return gpio_exp_set_pull_mode(gpio, mode, NULL);
 }
 
 esp_err_t gpio_set_direction_u(int gpio, gpio_mode_t mode) {
-	if (gpio < GPIO_EXP_BASE_MIN) return gpio_set_direction(gpio, mode);
+	if (gpio < GPIO_NUM_MAX) return gpio_set_direction(gpio, mode);
 	return gpio_exp_set_direction(gpio, mode, NULL);
 }
 
 int gpio_get_level_u(int gpio) {
-	if (gpio < GPIO_EXP_BASE_MIN) return gpio_get_level(gpio);
+	if (gpio < GPIO_NUM_MAX) return gpio_get_level(gpio);
 	return gpio_exp_get_level(gpio, 50, NULL);
 }
 
 esp_err_t gpio_set_level_u(int gpio, int level) {
-	if (gpio < GPIO_EXP_BASE_MIN) return gpio_set_level(gpio, level);
+	if (gpio < GPIO_NUM_MAX) return gpio_set_level(gpio, level);
 	return gpio_exp_set_level(gpio, level, false, NULL);
 }
 
diff --git a/components/services/gpio_exp.h b/components/services/gpio_exp.h
index 04404bbf..433dac66 100644
--- a/components/services/gpio_exp.h
+++ b/components/services/gpio_exp.h
@@ -12,8 +12,6 @@
 #include "freertos/FreeRTOS.h"
 #include "driver/gpio.h"
 
-#define GPIO_EXP_BASE_MIN	100
-
 struct gpio_exp_s;
 
 typedef struct {
diff --git a/components/services/led.c b/components/services/led.c
index 70abc69f..a56f2797 100644
--- a/components/services/led.c
+++ b/components/services/led.c
@@ -19,6 +19,7 @@
 #include "driver/gpio.h"
 #include "driver/ledc.h"
 #include "platform_config.h"
+#include "gpio_exp.h"
 #include "led.h"
 #include "globdefs.h"
 #include "accessors.h"
@@ -54,7 +55,7 @@ static int led_max = 2;
  * 
  */
 static void set_level(struct led_s *led, bool on) {
-	if (led->pwm < 0) gpio_set_level(led->gpio, on ? led->onstate : !led->onstate);
+	if (led->pwm < 0 || led->gpio >= GPIO_NUM_MAX) gpio_set_level_u(led->gpio, on ? led->onstate : !led->onstate);
 	else {
 		ledc_set_duty(LEDC_HIGH_SPEED_MODE, led->channel, on ? led->pwm : (led->onstate ? 0 : pwm_system.max));
 		ledc_update_duty(LEDC_HIGH_SPEED_MODE, led->channel);
diff --git a/components/services/services.c b/components/services/services.c
index 799dcec8..ea2b9b3c 100644
--- a/components/services/services.c
+++ b/components/services/services.c
@@ -12,6 +12,7 @@
 #include "driver/ledc.h"
 #include "driver/i2c.h"
 #include "platform_config.h"
+#include "gpio_exp.h"
 #include "battery.h"
 #include "led.h"
 #include "monitor.h"
@@ -44,12 +45,12 @@ void set_power_gpio(int gpio, char *value) {
 	if (!strcasecmp(value, "vcc") ) {
 		gpio_pad_select_gpio(gpio);
 		gpio_set_direction(gpio, GPIO_MODE_OUTPUT);
-		gpio_set_level(gpio, 1);
+		gpio_set_level_u(gpio, 1);
 	} else if (!strcasecmp(value, "gnd")) {
 		gpio_pad_select_gpio(gpio);
 		gpio_set_direction(gpio, GPIO_MODE_OUTPUT);
-		gpio_set_level(gpio, 0);
-	} else parsed = false	;
+		gpio_set_level_u(gpio, 0);
+	} else parsed = false;
 	
 	if (parsed) ESP_LOGI(TAG, "set GPIO %u to %s", gpio, value);
  }	
@@ -69,7 +70,11 @@ void services_init(void) {
 	}
 #endif
 
-	// set potential power GPIO
+	// create GPIO expander
+	const gpio_exp_config_t * gpio_exp_config = config_gpio_exp_get();
+	if (gpio_exp_config) gpio_exp_create(gpio_exp_config);
+
+	// set potential power GPIO (a GPIO-powered expander might be an issue)
 	parse_set_GPIO(set_power_gpio);
 
 	// shared I2C bus 
@@ -100,10 +105,6 @@ void services_init(void) {
 		ESP_LOGW(TAG, "no SPI configured");
 	}	
 
-	// create GPIO expander
-	const gpio_exp_config_t * gpio_exp_config = config_gpio_exp_get();
-	if (gpio_exp_config) gpio_exp_create(gpio_exp_config);
-
 	// system-wide PWM timer configuration
 	ledc_timer_config_t pwm_timer = {
 		.duty_resolution = LEDC_TIMER_13_BIT, 
diff --git a/components/squeezelite/output_i2s.c b/components/squeezelite/output_i2s.c
index bdc54b09..db83a60b 100644
--- a/components/squeezelite/output_i2s.c
+++ b/components/squeezelite/output_i2s.c
@@ -43,6 +43,7 @@ sure that using rate_delay would fix that
 #include "led.h"
 #include "monitor.h"
 #include "platform_config.h"
+#include "gpio_exp.h"
 #include "accessors.h"
 #include "equalizer.h"
 #include "globdefs.h"
@@ -131,10 +132,10 @@ static bool handler(u8_t *data, int len){
 			
 			if (jack_mutes_amp && jack_inserted_svc()) {
 				adac->speaker(false);
-				if (amp_control.gpio != -1) gpio_set_level(amp_control.gpio, !amp_control.active);
+				if (amp_control.gpio != -1) gpio_set_level_u(amp_control.gpio, !amp_control.active);
 			} else {
 				adac->speaker(true);
-				if (amp_control.gpio != -1) gpio_set_level(amp_control.gpio, amp_control.active);
+				if (amp_control.gpio != -1) gpio_set_level_u(amp_control.gpio, amp_control.active);
 			}	
 		}
 
@@ -157,7 +158,7 @@ static void jack_handler(bool inserted) {
 	if (jack_mutes_amp) {
 		LOG_INFO("switching amplifier %s", inserted ? "OFF" : "ON");
 		adac->speaker(!inserted);
-		if (amp_control.gpio != -1) gpio_set_level(amp_control.gpio, inserted ? !amp_control.active : amp_control.active);
+		if (amp_control.gpio != -1) gpio_set_level_u(amp_control.gpio, inserted ? !amp_control.active : amp_control.active);
 	}
 	
 	// activate headset
@@ -179,7 +180,7 @@ static void set_amp_gpio(int gpio, char *value) {
 		
 		gpio_pad_select_gpio(amp_control.gpio);
 		gpio_set_direction(amp_control.gpio, GPIO_MODE_OUTPUT);
-		gpio_set_level(amp_control.gpio, !amp_control.active);
+		gpio_set_level_u(amp_control.gpio, !amp_control.active);
 		
 		LOG_INFO("setting amplifier GPIO %d (active:%d)", amp_control.gpio, amp_control.active);
 	}	
@@ -455,14 +456,14 @@ static void output_thread_i2s(void *arg) {
 			LOG_INFO("Output state is %d", output.state);
 			if (output.state == OUTPUT_OFF) {
 				led_blink(LED_GREEN, 100, 2500);
-				if (amp_control.gpio != -1) gpio_set_level(amp_control.gpio, !amp_control.active);
+				if (amp_control.gpio != -1) gpio_set_level_u(amp_control.gpio, !amp_control.active);
 				LOG_INFO("switching off amp GPIO %d", amp_control.gpio);
 			} else if (output.state == OUTPUT_STOPPED) {
 				adac->speaker(false);
 				led_blink(LED_GREEN, 200, 1000);
 			} else if (output.state == OUTPUT_RUNNING) {
 				if (!jack_mutes_amp || !jack_inserted_svc()) {
-					if (amp_control.gpio != -1) gpio_set_level(amp_control.gpio, amp_control.active);
+					if (amp_control.gpio != -1) gpio_set_level_u(amp_control.gpio, amp_control.active);
 					adac->speaker(true);
 				}	
 				led_on(LED_GREEN);