diff --git a/cores/esp8266/core_esp8266_si2c.cpp b/cores/esp8266/core_esp8266_si2c.cpp
index 7200f6315..281b19680 100644
--- a/cores/esp8266/core_esp8266_si2c.cpp
+++ b/cores/esp8266/core_esp8266_si2c.cpp
@@ -128,6 +128,8 @@ private:
         }
     }
 
+    // Generate a clock "valley" (at the end of a segment, just before a repeated start)
+    void twi_scl_valley(void);
 
 public:
     void setClock(unsigned int freq);
@@ -386,13 +388,16 @@ unsigned char Twi::writeTo(unsigned char address, unsigned char * buf, unsigned
     {
         write_stop();
     }
+    else
+    {
+        twi_scl_valley();
+        // TD-er: Also busywait(twi_dcount) here?
+        // busywait(twi_dcount);
+    }
     i = 0;
     while (!SDA_READ() && (i++) < 10)
     {
-        SCL_LOW();
-        busywait(twi_dcount);
-        SCL_HIGH();
-        WAIT_CLOCK_STRETCH();
+        twi_scl_valley();
         busywait(twi_dcount);
     }
     return 0;
@@ -422,13 +427,16 @@ unsigned char Twi::readFrom(unsigned char address, unsigned char* buf, unsigned
     {
         write_stop();
     }
+    else
+    {
+        twi_scl_valley();
+        // TD-er: Also busywait(twi_dcount) here?
+        // busywait(twi_dcount);
+    }
     i = 0;
     while (!SDA_READ() && (i++) < 10)
     {
-        SCL_LOW();
-        busywait(twi_dcount);
-        SCL_HIGH();
-        WAIT_CLOCK_STRETCH();
+        twi_scl_valley();
         busywait(twi_dcount);
     }
     return 0;
@@ -649,6 +657,14 @@ void ICACHE_RAM_ATTR Twi::onTwipEvent(uint8_t status)
     }
 }
 
+void Twi::twi_scl_valley(void)
+{
+    SCL_LOW();
+    busywait(twi_dcount);
+    SCL_HIGH();
+    WAIT_CLOCK_STRETCH();
+}
+
 void ICACHE_RAM_ATTR Twi::onTimer(void *unused)
 {
     (void)unused;