diff --git a/hardware/esp8266com/esp8266/cores/esp8266/Esp.cpp b/hardware/esp8266com/esp8266/cores/esp8266/Esp.cpp
index 419cb889a..73367683a 100644
--- a/hardware/esp8266com/esp8266/cores/esp8266/Esp.cpp
+++ b/hardware/esp8266com/esp8266/cores/esp8266/Esp.cpp
@@ -19,6 +19,9 @@
  */
 
 #include "Arduino.h"
+#include "flash_utils.h"
+#include "eboot_command.h"
+#include <memory>
 
 extern "C" {
 #include "user_interface.h"
@@ -26,6 +29,9 @@ extern "C" {
 extern struct rst_info resetInfo;
 }
 
+
+// #define DEBUG_SERIAL Serial
+
 //extern "C" void ets_wdt_init(uint32_t val);
 extern "C" void ets_wdt_enable(void);
 extern "C" void ets_wdt_disable(void);
@@ -315,4 +321,123 @@ bool EspClass::eraseConfig(void) {
     return ret;
 }
 
+uint32_t EspClass::getSketchSize() {
+    static uint32_t result = 0;
+    if (result)
+        return result;
+
+    image_header_t image_header;
+    uint32_t pos = APP_START_OFFSET;
+    if (spi_flash_read(pos, (uint32_t*) &image_header, sizeof(image_header))) {
+        return 0;
+    }
+    pos += sizeof(image_header);
+#ifdef DEBUG_SERIAL
+    DEBUG_SERIAL.printf("num_segments=%u\r\n", image_header.num_segments);
+#endif
+    for (uint32_t section_index = 0;
+        section_index < image_header.num_segments; 
+        ++section_index)
+    {
+        section_header_t section_header = {0};
+        if (spi_flash_read(pos, (uint32_t*) &section_header, sizeof(section_header))) {
+            return 0;
+        }
+        pos += sizeof(section_header);
+        pos += section_header.size;
+#ifdef DEBUG_SERIAL
+        DEBUG_SERIAL.printf("section=%u size=%u pos=%u\r\n", section_index, section_header.size, pos);
+#endif
+    }
+    result = pos;
+    return result;
+}
+
+extern "C" uint32_t _SPIFFS_start;
+
+uint32_t EspClass::getFreeSketchSpace() {
+
+    uint32_t usedSize = getSketchSize();
+    // round one sector up
+    uint32_t freeSpaceStart = (usedSize + FLASH_SECTOR_SIZE - 1) & (~(FLASH_SECTOR_SIZE - 1));
+    uint32_t freeSpaceEnd = (uint32_t)&_SPIFFS_start - 0x40200000;
+
+#ifdef DEBUG_SERIAL
+    DEBUG_SERIAL.printf("usedSize=%u freeSpaceStart=%u freeSpaceEnd=%u\r\n", usedSize, freeSpaceStart, freeSpaceEnd);
+#endif
+    return freeSpaceEnd - freeSpaceStart;
+}
+
+bool EspClass::updateSketch(Stream& in, uint32_t size) {
+
+    if (size > getFreeSketchSpace())
+        return false;
+
+    uint32_t usedSize = getSketchSize();
+    uint32_t freeSpaceStart = (usedSize + FLASH_SECTOR_SIZE - 1) & (~(FLASH_SECTOR_SIZE - 1));
+    uint32_t roundedSize = (size + FLASH_SECTOR_SIZE - 1) & (~(FLASH_SECTOR_SIZE - 1));
+
+#ifdef DEBUG_SERIAL
+    DEBUG_SERIAL.printf("erase @0x%x size=0x%x\r\n", freeSpaceStart, roundedSize);
+#endif
+
+    noInterrupts();
+    int rc = SPIEraseAreaEx(freeSpaceStart, roundedSize);
+    interrupts();
+    if (rc)
+        return false;
+
+#ifdef DEBUG_SERIAL
+    DEBUG_SERIAL.println("erase done");
+#endif
+
+    uint32_t addr = freeSpaceStart;
+    uint32_t left = size;
+
+    const uint32_t bufferSize = FLASH_SECTOR_SIZE;
+    std::unique_ptr<uint8_t> buffer(new uint8_t[bufferSize]);
+
+#ifdef DEBUG_SERIAL
+    DEBUG_SERIAL.println("writing");
+#endif
+    while (left > 0) {
+        size_t willRead = (left < bufferSize) ? left : bufferSize;
+        size_t rd = in.readBytes(buffer.get(), willRead);
+        if (rd != willRead) {
+#ifdef DEBUG_SERIAL
+            DEBUG_SERIAL.println("stream read failed");
+#endif
+            return false;
+        }
+
+        noInterrupts();
+        rc = SPIWrite(addr, buffer.get(), willRead);
+        interrupts();
+        if (rc) {
+#ifdef DEBUG_SERIAL
+            DEBUG_SERIAL.println("write failed");
+#endif            
+            return false;
+        }
+
+        addr += willRead;
+        left -= willRead;
+#ifdef DEBUG_SERIAL
+        DEBUG_SERIAL.print(".");
+#endif
+    }
+
+#ifdef DEBUG_SERIAL
+    DEBUG_SERIAL.println("\r\nrestarting");
+#endif
+    eboot_command ebcmd;
+    ebcmd.action = ACTION_COPY_RAW;
+    ebcmd.args[0] = freeSpaceStart;
+    ebcmd.args[1] = 0x00000;
+    ebcmd.args[2] = size;
+    eboot_command_write(&ebcmd);
+    
+    ESP.restart();
+    return true; // never happens
+}
 
diff --git a/hardware/esp8266com/esp8266/cores/esp8266/Esp.h b/hardware/esp8266com/esp8266/cores/esp8266/Esp.h
index ecb80da07..2b58b79d1 100644
--- a/hardware/esp8266com/esp8266/cores/esp8266/Esp.h
+++ b/hardware/esp8266com/esp8266/cores/esp8266/Esp.h
@@ -69,44 +69,48 @@ class EspClass {
         // note: setting the timeout value is not implemented at the moment
         void wdtEnable(WDTO_t timeout_ms = WDTO_0MS);
 
-        void wdtDisable(void);
-        void wdtFeed(void);
+        void wdtDisable();
+        void wdtFeed();
 
         void deepSleep(uint32_t time_us, WakeMode mode = WAKE_RF_DEFAULT);
 
-        void reset(void);
-        void restart(void);
+        void reset();
+        void restart();
 
-        uint16_t getVcc(void);
-        uint32_t getFreeHeap(void);
+        uint16_t getVcc();
+        uint32_t getFreeHeap();
 
-        uint32_t getChipId(void);
+        uint32_t getChipId();
 
-        const char * getSdkVersion(void);
+        const char * getSdkVersion();
 
-        uint8_t getBootVersion(void);
-        uint8_t getBootMode(void);
+        uint8_t getBootVersion();
+        uint8_t getBootMode();
 
-        uint8_t getCpuFreqMHz(void);
+        uint8_t getCpuFreqMHz();
 
-        uint32_t getFlashChipId(void);
+        uint32_t getFlashChipId();
         //gets the actual chip size based on the flash id
-        uint32_t getFlashChipRealSize(void);
+        uint32_t getFlashChipRealSize();
         //gets the size of the flash as set by the compiler
-        uint32_t getFlashChipSize(void);
-        uint32_t getFlashChipSpeed(void);
-        FlashMode_t getFlashChipMode(void);
-        uint32_t getFlashChipSizeByChipId(void);
+        uint32_t getFlashChipSize();
+        uint32_t getFlashChipSpeed();
+        FlashMode_t getFlashChipMode();
+        uint32_t getFlashChipSizeByChipId();
 
-        String getResetInfo(void);
-        struct rst_info * getResetInfoPtr(void);
+        uint32_t getSketchSize();
+        uint32_t getFreeSketchSpace();
+        bool updateSketch(Stream& in, uint32_t size);
 
-        bool eraseConfig(void);
+        String getResetInfo();
+        struct rst_info * getResetInfoPtr();
 
-        inline uint32_t getCycleCount(void);
+        bool eraseConfig();
+
+        inline uint32_t getCycleCount();
 };
 
-uint32_t EspClass::getCycleCount(void)
+uint32_t EspClass::getCycleCount()
 {
     uint32_t ccount;
     __asm__ __volatile__("rsr %0,ccount":"=a" (ccount));
diff --git a/hardware/esp8266com/esp8266/cores/esp8266/core_esp8266_eboot_command.c b/hardware/esp8266com/esp8266/cores/esp8266/core_esp8266_eboot_command.c
new file mode 100644
index 000000000..60c92bf18
--- /dev/null
+++ b/hardware/esp8266com/esp8266/cores/esp8266/core_esp8266_eboot_command.c
@@ -0,0 +1,88 @@
+/* 
+ core_esp8266_eboot_command.c - interface to the eboot bootloader
+
+ Copyright (c) 2015 Ivan Grokhotkov. All rights reserved.
+ This file is part of the esp8266 core for Arduino environment.
+ 
+ This library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ This library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with this library; if not, write to the Free Software
+ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <stddef.h>
+#include <stdbool.h>
+#include "eboot_command.h"
+
+uint32_t crc_update(uint32_t crc, const uint8_t *data, size_t length)
+{
+    uint32_t i;
+    bool bit;
+    uint8_t c;
+    
+    while (length--) {
+        c = *data++;
+        for (i = 0x80; i > 0; i >>= 1) {
+            bit = crc & 0x80000000;
+            if (c & i) {
+                bit = !bit;
+            }
+            crc <<= 1;
+            if (bit) {
+                crc ^= 0x04c11db7;
+            }
+        }
+    }
+    return crc;
+}
+
+uint32_t eboot_command_calculate_crc32(const struct eboot_command* cmd)
+{
+    return crc_update(0xffffffff, (const uint8_t*) cmd, 
+                      offsetof(struct eboot_command, crc32));
+}
+
+int eboot_command_read(struct eboot_command* cmd)
+{
+    const uint32_t dw_count = sizeof(struct eboot_command) / sizeof(uint32_t);
+    uint32_t* dst = (uint32_t *) cmd;
+    for (uint32_t i = 0; i < dw_count; ++i) {
+        dst[i] = RTC_MEM[i];
+    }
+
+    uint32_t crc32 = eboot_command_calculate_crc32(cmd);
+    if (cmd->magic & EBOOT_MAGIC_MASK != EBOOT_MAGIC || 
+        cmd->crc32 != crc32) {
+        return 1;
+    }
+
+    return 0;
+}
+
+void eboot_command_write(struct eboot_command* cmd)
+{
+    cmd->magic = EBOOT_MAGIC;
+    cmd->crc32 = eboot_command_calculate_crc32(cmd);
+
+    const uint32_t dw_count = sizeof(struct eboot_command) / sizeof(uint32_t);
+    const uint32_t* src = (const uint32_t *) cmd;
+    for (uint32_t i = 0; i < dw_count; ++i) {
+        RTC_MEM[i] = src[i];
+    }
+}
+
+void eboot_command_clear()
+{
+    RTC_MEM[offsetof(struct eboot_command, magic) / sizeof(uint32_t)] = 0;
+    RTC_MEM[offsetof(struct eboot_command, crc32) / sizeof(uint32_t)] = 0;
+}
+
diff --git a/hardware/esp8266com/esp8266/cores/esp8266/core_esp8266_flash_utils.c b/hardware/esp8266com/esp8266/cores/esp8266/core_esp8266_flash_utils.c
new file mode 100644
index 000000000..6f8a34f41
--- /dev/null
+++ b/hardware/esp8266com/esp8266/cores/esp8266/core_esp8266_flash_utils.c
@@ -0,0 +1,64 @@
+/* 
+ core_esp8266_flash_utils.c - flash and binary image helpers
+
+ Copyright (c) 2015 Ivan Grokhotkov. All rights reserved.
+ This file is part of the esp8266 core for Arduino environment.
+ 
+ This library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ This library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with this library; if not, write to the Free Software
+ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include "flash_utils.h"
+
+
+int SPIEraseAreaEx(const uint32_t start, const uint32_t size)
+{
+    if (start & (FLASH_SECTOR_SIZE - 1) != 0) {
+        return 1;
+    }
+
+    const uint32_t sectors_per_block = FLASH_BLOCK_SIZE / FLASH_SECTOR_SIZE;
+    uint32_t current_sector = start / FLASH_SECTOR_SIZE;
+    uint32_t sector_count = (size + FLASH_SECTOR_SIZE - 1) / FLASH_SECTOR_SIZE;
+    const uint32_t end = current_sector + sector_count;
+
+    for (; current_sector < end && (current_sector & (sectors_per_block-1)); 
+        ++current_sector, --sector_count) {
+        if (SPIEraseSector(current_sector)) {
+            return 2;
+        }
+    }
+
+    for (;current_sector + sectors_per_block <= end; 
+        current_sector += sectors_per_block, 
+        sector_count -= sectors_per_block) {
+        if (SPIEraseBlock(current_sector / sectors_per_block)) {
+            return 3;
+        }
+    }
+
+    for (; current_sector < end; 
+        ++current_sector, --sector_count) {
+        if (SPIEraseSector(current_sector)) {
+            return 4;
+        }
+    }
+
+    return 0;
+}
+
diff --git a/hardware/esp8266com/esp8266/cores/esp8266/eboot_command.h b/hardware/esp8266com/esp8266/cores/esp8266/eboot_command.h
new file mode 100644
index 000000000..3d854afba
--- /dev/null
+++ b/hardware/esp8266com/esp8266/cores/esp8266/eboot_command.h
@@ -0,0 +1,36 @@
+#ifndef EBOOT_COMMAND_H
+#define EBOOT_COMMAND_H
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define RTC_MEM ((volatile uint32_t*)0x60001200)
+
+enum action_t {
+    ACTION_COPY_RAW = 0x00000001,
+    ACTION_LOAD_APP = 0xffffffff
+};
+
+#define EBOOT_MAGIC 	 0xeb001000
+#define EBOOT_MAGIC_MASK 0xfffff000
+
+struct eboot_command {
+    uint32_t magic;
+    enum action_t action;
+    uint32_t args[29];
+    uint32_t crc32;
+};
+
+
+int eboot_command_read(struct eboot_command* cmd);
+void eboot_command_write(struct eboot_command* cmd);
+void eboot_command_clear();
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif //EBOOT_COMMAND_H
diff --git a/hardware/esp8266com/esp8266/cores/esp8266/flash_utils.h b/hardware/esp8266com/esp8266/cores/esp8266/flash_utils.h
new file mode 100644
index 000000000..4e5f2120b
--- /dev/null
+++ b/hardware/esp8266com/esp8266/cores/esp8266/flash_utils.h
@@ -0,0 +1,63 @@
+/*
+ flash_utils.h - Flash access function and data structures
+ Copyright (c) 2015 Ivan Grokhotkov.  All right reserved.
+
+ This library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ This library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with this library; if not, write to the Free Software
+ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+
+#ifndef FLASH_UTILS_H
+#define FLASH_UTILS_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int SPIEraseBlock(uint32_t block);
+int SPIEraseSector(uint32_t sector);
+int SPIRead(uint32_t addr, void *dest, size_t size);
+int SPIWrite(uint32_t addr, void *src, size_t size);
+int SPIEraseAreaEx(const uint32_t start, const uint32_t size);
+
+#define FLASH_SECTOR_SIZE 0x1000
+#define FLASH_BLOCK_SIZE 0x10000
+#define APP_START_OFFSET 0x1000
+
+typedef struct {
+    unsigned char       magic;
+    unsigned char       num_segments;
+
+    /* SPI Flash Interface (0 = QIO, 1 = QOUT, 2 = DIO, 0x3 = DOUT) */
+    unsigned char       flash_mode;
+
+    /* High four bits: 0 = 512K, 1 = 256K, 2 = 1M, 3 = 2M, 4 = 4M, 
+       Low four bits:  0 = 40MHz, 1= 26MHz, 2 = 20MHz, 0xf = 80MHz */
+    unsigned char		flash_size_freq;
+
+    uint32_t            entry;
+} image_header_t;
+
+
+typedef struct {
+    uint32_t            address;
+    uint32_t            size;
+} section_header_t;
+
+#ifdef __cplusplus
+}
+#endif
+
+
+#endif //FLASH_UTILS_H