diff --git a/boards.txt b/boards.txt
index 3faf8b2ba..e2b1c4384 100644
--- a/boards.txt
+++ b/boards.txt
@@ -1,7 +1,7 @@
 ##############################################################
 esp01.name=ESP-01
 
-esp01.upload.tool=esptool
+esp01.upload.tool=esptoolpy
 esp01.upload.speed=57600
 esp01.upload.wait_for_upload_port=true
 
diff --git a/cores/esp8266/HardwareSerial.cpp b/cores/esp8266/HardwareSerial.cpp
index 9708f7d91..ca174b974 100644
--- a/cores/esp8266/HardwareSerial.cpp
+++ b/cores/esp8266/HardwareSerial.cpp
@@ -208,15 +208,25 @@ void serial_rx_handler(char c)
 {
     Serial._rx_complete_irq(c);
 }
+extern "C" size_t ets_printf(const char*, ...);
+
+HardwareSerial::HardwareSerial() : 
+    _rx_buffer_head(0), _rx_buffer_tail(0),
+    _tx_buffer_head(0), _tx_buffer_tail(0),
+    _uart(0)
+{
+}
 
 void HardwareSerial::begin(unsigned long baud, byte config)
 {
     _uart = uart0_init(baud, &serial_rx_handler);
+    _written = false;
 }
 
 void HardwareSerial::end()
 {
     uart0_uninit(_uart);
+    _uart = 0;
 }
 
 int HardwareSerial::available(void)
@@ -263,7 +273,7 @@ void HardwareSerial::flush()
 
 size_t HardwareSerial::write(uint8_t c)
 {
-    WRITE_PERI_REG(UART_FIFO(0), c);
+    uart0_transmit_char(_uart, c);
     // // If the buffer and the data register is empty, just write the byte
     // // to the data register and be done. This shortcut helps
     // // significantly improve the effective datarate at high (>
@@ -294,9 +304,9 @@ size_t HardwareSerial::write(uint8_t c)
     // _tx_buffer_head = i;
     
     // sbi(*_ucsrb, UDRIE0);
-    // _written = true;
+    _written = true;
     
-    // return 1;
+    return 1;
 }
 
 void HardwareSerial::_rx_complete_irq(char c)
diff --git a/cores/esp8266/HardwareSerial.h b/cores/esp8266/HardwareSerial.h
index 8c4810fc3..1311c0939 100644
--- a/cores/esp8266/HardwareSerial.h
+++ b/cores/esp8266/HardwareSerial.h
@@ -80,7 +80,7 @@ class HardwareSerial : public Stream
     unsigned char _tx_buffer[SERIAL_TX_BUFFER_SIZE];
 
   public:
-    HardwareSerial() : _uart(0) { }
+    HardwareSerial();
 
     void begin(unsigned long baud) { begin(baud, 0); }
     void begin(unsigned long, uint8_t);
diff --git a/cores/esp8266/main.cpp b/cores/esp8266/main.cpp
index c77762656..7a2c26273 100644
--- a/cores/esp8266/main.cpp
+++ b/cores/esp8266/main.cpp
@@ -114,7 +114,7 @@ void user_init(void)
                     g_loop_queue,
                     LOOP_QUEUE_SIZE);
 
-    system_init_done_cb(&esp_schedule);
+    system_init_done_cb(&init_done);
 }
 }
 
diff --git a/platform.txt b/platform.txt
index 70c9f4a0f..0349451df 100644
--- a/platform.txt
+++ b/platform.txt
@@ -80,9 +80,9 @@ recipe.size.regex.eeprom=^(?:\.eeprom)\s+([0-9]+).*
 
 # ------------------------------
 
-tools.esptoolpy.cmd.path={runtime.ide.path}/hardware/tools/esptool.py
+tools.esptoolpy.cmd.path={runtime.ide.path}/hardware/tools/esp8266/espflash
 
 tools.esptoolpy.program.params.verbose=
 tools.esptoolpy.program.params.quiet=
-tools.esptoolpy.program.pattern="python {cmd.path}" --port={serial.port} write_flash 0x00000 "{build.path}/{build.project_name}._00000.bin"
+tools.esptoolpy.program.pattern="{cmd.path}" --port={serial.port} write_flash 0x00000 "{build.path}/{build.project_name}_00000.bin" 0x40000 "{build.path}/{build.project_name}_40000.bin"