diff --git a/pkg/ucglib/src/csrc/ucg_riotos.c b/pkg/ucglib/src/csrc/ucg_riotos.c
index 892847b876..bf10f22e75 100644
--- a/pkg/ucglib/src/csrc/ucg_riotos.c
+++ b/pkg/ucglib/src/csrc/ucg_riotos.c
@@ -53,7 +53,7 @@ static void ucg_enable_pins(gpio_t *pins, uint32_t pins_enabled)
     uint8_t i;
 
     for (i = 0; i < 32; i++) {
-        if (pins_enabled & (1 << i)) {
+        if (pins_enabled & ((uint32_t)1 << i)) {
             if (pins[i] != GPIO_UNDEF) {
                 if (i < UCG_PIN_COUNT) {
                     gpio_init(pins[i], GPIO_OUT);
diff --git a/sys/random/fortuna/fortuna.c b/sys/random/fortuna/fortuna.c
index f1d801dd26..1e3f197219 100755
--- a/sys/random/fortuna/fortuna.c
+++ b/sys/random/fortuna/fortuna.c
@@ -184,7 +184,7 @@ int fortuna_random_data(fortuna_state_t *state, uint8_t *out, size_t bytes)
         size_t len = 0;
 
         for (int i = 0; i < (int) FORTUNA_POOLS; i++) {
-            if (state->reseeds | (1 << i)) {
+            if (state->reseeds | ((uint32_t)1 << i)) {
                 sha256_final(&state->pools[i].ctx, &buf[len]);
                 sha256_init(&state->pools[i].ctx);
                 state->pools[i].len = 0;