diff --git a/cores/esp8266/core_esp8266_wiring_pulse.cpp b/cores/esp8266/core_esp8266_wiring_pulse.cpp
index 8e124ac312..b20bdb4c45 100644
--- a/cores/esp8266/core_esp8266_wiring_pulse.cpp
+++ b/cores/esp8266/core_esp8266_wiring_pulse.cpp
@@ -26,13 +26,20 @@ extern "C" {
 
 extern uint32_t xthal_get_ccount();
 
-#define WAIT_FOR_PIN_STATE(state) \
-    while (digitalRead(pin) != (state)) { \
-        if (xthal_get_ccount() - start_cycle_count > timeout_cycles) { \
-            return 0; \
-        } \
-        optimistic_yield(5000); \
+namespace {
+    inline __attribute__((always_inline)) bool waitForPinState(
+        const uint8_t pin, const uint8_t state,
+        const uint32_t timeout_cycles, const uint32_t start_cycle_count)
+    {
+        while (digitalRead(pin) != state) {
+            if (xthal_get_ccount() - start_cycle_count > timeout_cycles) {
+                return false;
+            }
+            optimistic_yield(1000);
+        }
+        return true;
     }
+}
 
 // max timeout is 27 seconds at 160MHz clock and 54 seconds at 80MHz clock
 unsigned long pulseIn(uint8_t pin, uint8_t state, unsigned long timeout)
@@ -43,10 +50,16 @@ unsigned long pulseIn(uint8_t pin, uint8_t state, unsigned long timeout)
     }
     const uint32_t timeout_cycles = microsecondsToClockCycles(timeout);
     const uint32_t start_cycle_count = xthal_get_ccount();
-    WAIT_FOR_PIN_STATE(!state);
-    WAIT_FOR_PIN_STATE(state);
+    if (!waitForPinState(pin, !state, timeout_cycles, start_cycle_count)) {
+        return 0;
+    }
+    if (!waitForPinState(pin, state, timeout_cycles, start_cycle_count)) {
+        return 0;
+    }
     const uint32_t pulse_start_cycle_count = xthal_get_ccount();
-    WAIT_FOR_PIN_STATE(!state);
+    if (!waitForPinState(pin, !state, timeout_cycles, start_cycle_count)) {
+        return 0;
+    }
     return clockCyclesToMicroseconds(xthal_get_ccount() - pulse_start_cycle_count);
 }
 
diff --git a/cores/esp8266/uart.cpp b/cores/esp8266/uart.cpp
index 802072d438..de57ff880a 100644
--- a/cores/esp8266/uart.cpp
+++ b/cores/esp8266/uart.cpp
@@ -510,7 +510,10 @@ uart_tx_fifo_full(const int uart_nr)
 static void
 uart_do_write_char(const int uart_nr, char c)
 {
-    while(uart_tx_fifo_full(uart_nr));
+    while(uart_tx_fifo_full(uart_nr))
+    {
+        optimistic_yield(10000UL);
+    }
 
     USF(uart_nr) = c;
 }
@@ -544,7 +547,6 @@ uart_write(uart_t* uart, const char* buf, size_t size)
     const int uart_nr = uart->uart_nr;
     while (size--) {
         uart_do_write_char(uart_nr, pgm_read_byte(buf++));
-        optimistic_yield(10000UL);
     }
 
     return ret;
diff --git a/libraries/ESP8266WiFi/src/WiFiUdp.cpp b/libraries/ESP8266WiFi/src/WiFiUdp.cpp
index a45659d844..8a7e0cff0b 100644
--- a/libraries/ESP8266WiFi/src/WiFiUdp.cpp
+++ b/libraries/ESP8266WiFi/src/WiFiUdp.cpp
@@ -117,7 +117,7 @@ int WiFiUDP::available() {
     if (!result) {
         // yielding here will not make more data "available",
         // but it will prevent the system from going into WDT reset
-        optimistic_yield(1000);
+        optimistic_yield(100UL);
     }
 
     return result;
@@ -194,7 +194,7 @@ int WiFiUDP::parsePacket()
         return 0;
 
     if (!_ctx->next()) {
-        optimistic_yield(100);
+        optimistic_yield(100UL);
         return 0;
     }
 
diff --git a/libraries/Wire/Wire.cpp b/libraries/Wire/Wire.cpp
index b2d9a6affc..a68b8962ba 100644
--- a/libraries/Wire/Wire.cpp
+++ b/libraries/Wire/Wire.cpp
@@ -227,7 +227,7 @@ int TwoWire::available(void)
     {
         // yielding here will not make more data "available",
         // but it will prevent the system from going into WDT reset
-        optimistic_yield(1000);
+        optimistic_yield(100UL);
     }
 
     return result;