diff --git a/README.md b/README.md
index 6b085aa5c9..f333e8623c 100644
--- a/README.md
+++ b/README.md
@@ -3,7 +3,7 @@ Arduino core for ESP8266 WiFi chip
 
 # Quick links
 
-- [Latest release documentation](https://arduino-esp8266.readthedocs.io/en/2.7.1/)
+- [Latest release documentation](https://arduino-esp8266.readthedocs.io/en/2.7.3/)
 - [Current "git version" documentation](https://arduino-esp8266.readthedocs.io/en/latest/)
 - [Install git version](https://arduino-esp8266.readthedocs.io/en/latest/installing.html#using-git-version) ([sources](doc/installing.rst#using-git-version))
 
@@ -36,7 +36,7 @@ Starting with 1.6.4, Arduino allows installation of third-party platform package
 #### Latest release [![Latest release](https://img.shields.io/github/release/esp8266/Arduino.svg)](https://github.com/esp8266/Arduino/releases/latest/)
 Boards manager link: `https://arduino.esp8266.com/stable/package_esp8266com_index.json`
 
-Documentation: [https://arduino-esp8266.readthedocs.io/en/2.7.1/](https://arduino-esp8266.readthedocs.io/en/2.7.1/)
+Documentation: [https://arduino-esp8266.readthedocs.io/en/2.7.3/](https://arduino-esp8266.readthedocs.io/en/2.7.3/)
 
 ### Using git version
 [![Linux build status](https://travis-ci.org/esp8266/Arduino.svg)](https://travis-ci.org/esp8266/Arduino)
diff --git a/boards.txt b/boards.txt
index 3d2c355c29..8279cd5c53 100644
--- a/boards.txt
+++ b/boards.txt
@@ -5458,9 +5458,76 @@ gen4iod.menu.ssl.all.build.sslflags=
 gen4iod.menu.ssl.basic=Basic SSL ciphers (lower ROM use)
 gen4iod.menu.ssl.basic.build.sslflags=-DBEARSSL_SSL_BASIC
 gen4iod.upload.resetmethod=--before default_reset --after hard_reset
-gen4iod.build.flash_mode=dio
-gen4iod.build.flash_flags=-DFLASHMODE_DIO
+gen4iod.menu.FlashMode.dout=DOUT (compatible)
+gen4iod.menu.FlashMode.dout.build.flash_mode=dout
+gen4iod.menu.FlashMode.dout.build.flash_flags=-DFLASHMODE_DOUT
+gen4iod.menu.FlashMode.dio=DIO
+gen4iod.menu.FlashMode.dio.build.flash_mode=dio
+gen4iod.menu.FlashMode.dio.build.flash_flags=-DFLASHMODE_DIO
+gen4iod.menu.FlashMode.qout=QOUT
+gen4iod.menu.FlashMode.qout.build.flash_mode=qout
+gen4iod.menu.FlashMode.qout.build.flash_flags=-DFLASHMODE_QOUT
+gen4iod.menu.FlashMode.qio=QIO (fast)
+gen4iod.menu.FlashMode.qio.build.flash_mode=qio
+gen4iod.menu.FlashMode.qio.build.flash_flags=-DFLASHMODE_QIO
 gen4iod.build.flash_freq=80
+gen4iod.menu.eesz.2M64=2MB (FS:64KB OTA:~992KB)
+gen4iod.menu.eesz.2M64.build.flash_size=2M
+gen4iod.menu.eesz.2M64.build.flash_size_bytes=0x200000
+gen4iod.menu.eesz.2M64.build.flash_ld=eagle.flash.2m64.ld
+gen4iod.menu.eesz.2M64.build.spiffs_pagesize=256
+gen4iod.menu.eesz.2M64.upload.maximum_size=1044464
+gen4iod.menu.eesz.2M64.build.rfcal_addr=0x1FC000
+gen4iod.menu.eesz.2M64.build.spiffs_start=0x1F0000
+gen4iod.menu.eesz.2M64.build.spiffs_end=0x1FB000
+gen4iod.menu.eesz.2M64.build.spiffs_blocksize=4096
+gen4iod.menu.eesz.2M128=2MB (FS:128KB OTA:~960KB)
+gen4iod.menu.eesz.2M128.build.flash_size=2M
+gen4iod.menu.eesz.2M128.build.flash_size_bytes=0x200000
+gen4iod.menu.eesz.2M128.build.flash_ld=eagle.flash.2m128.ld
+gen4iod.menu.eesz.2M128.build.spiffs_pagesize=256
+gen4iod.menu.eesz.2M128.upload.maximum_size=1044464
+gen4iod.menu.eesz.2M128.build.rfcal_addr=0x1FC000
+gen4iod.menu.eesz.2M128.build.spiffs_start=0x1E0000
+gen4iod.menu.eesz.2M128.build.spiffs_end=0x1FB000
+gen4iod.menu.eesz.2M128.build.spiffs_blocksize=4096
+gen4iod.menu.eesz.2M256=2MB (FS:256KB OTA:~896KB)
+gen4iod.menu.eesz.2M256.build.flash_size=2M
+gen4iod.menu.eesz.2M256.build.flash_size_bytes=0x200000
+gen4iod.menu.eesz.2M256.build.flash_ld=eagle.flash.2m256.ld
+gen4iod.menu.eesz.2M256.build.spiffs_pagesize=256
+gen4iod.menu.eesz.2M256.upload.maximum_size=1044464
+gen4iod.menu.eesz.2M256.build.rfcal_addr=0x1FC000
+gen4iod.menu.eesz.2M256.build.spiffs_start=0x1C0000
+gen4iod.menu.eesz.2M256.build.spiffs_end=0x1FB000
+gen4iod.menu.eesz.2M256.build.spiffs_blocksize=4096
+gen4iod.menu.eesz.2M512=2MB (FS:512KB OTA:~768KB)
+gen4iod.menu.eesz.2M512.build.flash_size=2M
+gen4iod.menu.eesz.2M512.build.flash_size_bytes=0x200000
+gen4iod.menu.eesz.2M512.build.flash_ld=eagle.flash.2m512.ld
+gen4iod.menu.eesz.2M512.build.spiffs_pagesize=256
+gen4iod.menu.eesz.2M512.upload.maximum_size=1044464
+gen4iod.menu.eesz.2M512.build.rfcal_addr=0x1FC000
+gen4iod.menu.eesz.2M512.build.spiffs_start=0x180000
+gen4iod.menu.eesz.2M512.build.spiffs_end=0x1FA000
+gen4iod.menu.eesz.2M512.build.spiffs_blocksize=8192
+gen4iod.menu.eesz.2M1M=2MB (FS:1MB OTA:~512KB)
+gen4iod.menu.eesz.2M1M.build.flash_size=2M
+gen4iod.menu.eesz.2M1M.build.flash_size_bytes=0x200000
+gen4iod.menu.eesz.2M1M.build.flash_ld=eagle.flash.2m1m.ld
+gen4iod.menu.eesz.2M1M.build.spiffs_pagesize=256
+gen4iod.menu.eesz.2M1M.upload.maximum_size=1044464
+gen4iod.menu.eesz.2M1M.build.rfcal_addr=0x1FC000
+gen4iod.menu.eesz.2M1M.build.spiffs_start=0x100000
+gen4iod.menu.eesz.2M1M.build.spiffs_end=0x1FA000
+gen4iod.menu.eesz.2M1M.build.spiffs_blocksize=8192
+gen4iod.menu.eesz.2M=2MB (FS:none OTA:~1019KB)
+gen4iod.menu.eesz.2M.build.flash_size=2M
+gen4iod.menu.eesz.2M.build.flash_size_bytes=0x200000
+gen4iod.menu.eesz.2M.build.flash_ld=eagle.flash.2m.ld
+gen4iod.menu.eesz.2M.build.spiffs_pagesize=256
+gen4iod.menu.eesz.2M.upload.maximum_size=1044464
+gen4iod.menu.eesz.2M.build.rfcal_addr=0x1FC000
 gen4iod.menu.eesz.512K32=512KB (FS:32KB OTA:~230KB)
 gen4iod.menu.eesz.512K32.build.flash_size=512K
 gen4iod.menu.eesz.512K32.build.flash_size_bytes=0x80000
diff --git a/bootloaders/eboot/eboot.c b/bootloaders/eboot/eboot.c
index be67b0b6fe..0a38a88416 100644
--- a/bootloaders/eboot/eboot.c
+++ b/bootloaders/eboot/eboot.c
@@ -230,6 +230,7 @@ int main()
 
         ets_putc('0'+res); ets_putc('\n');
 
+/** disabled in 2.7.3
         // Verify the copy
         ets_putc('c'); ets_putc('m'); ets_putc('p'); ets_putc(':');
         if (res == 0) {
@@ -237,8 +238,9 @@ int main()
             res = copy_raw(cmd.args[0], cmd.args[1], cmd.args[2], true);
             ets_wdt_enable();
             }
-
         ets_putc('0'+res); ets_putc('\n');
+**/
+
         if (res == 0) {
             cmd.action = ACTION_LOAD_APP;
             cmd.args[0] = cmd.args[1];
diff --git a/bootloaders/eboot/eboot.elf b/bootloaders/eboot/eboot.elf
index 60329d847e..c6e56d7d14 100755
Binary files a/bootloaders/eboot/eboot.elf and b/bootloaders/eboot/eboot.elf differ
diff --git a/cores/esp8266/Updater.cpp b/cores/esp8266/Updater.cpp
index 351a57746b..03bc5c3f8f 100644
--- a/cores/esp8266/Updater.cpp
+++ b/cores/esp8266/Updater.cpp
@@ -35,6 +35,7 @@ UpdaterClass::UpdaterClass()
 , _startAddress(0)
 , _currentAddress(0)
 , _command(U_FLASH)
+, _ledPin(-1)
 , _hash(nullptr)
 , _verify(nullptr)
 , _progress_callback(nullptr)
diff --git a/cores/esp8266/heap.cpp b/cores/esp8266/heap.cpp
index 2001579ef0..3f549716f4 100644
--- a/cores/esp8266/heap.cpp
+++ b/cores/esp8266/heap.cpp
@@ -164,7 +164,7 @@ void ICACHE_RAM_ATTR print_loc(size_t size, const char* file, int line)
         if (inISR && (uint32_t)file >= 0x40200000) {
             DEBUG_HEAP_PRINTF("File: %p", file);
         } else if (!inISR && (uint32_t)file >= 0x40200000) {
-            char buf[ets_strlen(file)] __attribute__ ((aligned(4)));
+            char buf[ets_strlen(file) + 1] __attribute__((aligned(4)));
             ets_strcpy(buf, file);
             DEBUG_HEAP_PRINTF(buf);
         } else {
diff --git a/cores/esp8266/umm_malloc/umm_local.c b/cores/esp8266/umm_malloc/umm_local.c
index 8f83f4b4ac..392ef13c8f 100644
--- a/cores/esp8266/umm_malloc/umm_local.c
+++ b/cores/esp8266/umm_malloc/umm_local.c
@@ -206,7 +206,7 @@ int ICACHE_FLASH_ATTR umm_info_safe_printf_P(const char *fmt, ...) {
       the PROGMEM address must be word (4 bytes) aligned. The destination
       address for ets_memcpy must also be word-aligned.
     */
-    char ram_buf[ets_strlen(fmt)] __attribute__ ((aligned(4)));
+    char ram_buf[ets_strlen(fmt) + 1] __attribute__((aligned(4)));
     ets_strcpy(ram_buf, fmt);
     va_list argPtr;
     va_start(argPtr, fmt);
diff --git a/doc/boards.rst b/doc/boards.rst
index 7ab98e2513..9c94b63120 100644
--- a/doc/boards.rst
+++ b/doc/boards.rst
@@ -413,7 +413,7 @@ Datasheet and associated downloads can be found on the 4D Systems product page.
 
 The gen4-IoD range can be programmed using the Arduino IDE and also the 4D Systems Workshop4 IDE, which incorporates many additional graphics benefits. GFX4d library is available, along with a number of demo applications.
 
-- Product page: http://www.4dsystems.com.au/product/gen4-IoD
+- Product page: https://4dsystems.com.au/products/iot-display-modules
 
 Digistump Oak
 -------------
diff --git a/libraries/ESP8266WiFi/src/ESP8266WiFiGeneric.cpp b/libraries/ESP8266WiFi/src/ESP8266WiFiGeneric.cpp
index 41d771fb6a..2a5f96cb5d 100644
--- a/libraries/ESP8266WiFi/src/ESP8266WiFiGeneric.cpp
+++ b/libraries/ESP8266WiFi/src/ESP8266WiFiGeneric.cpp
@@ -233,6 +233,16 @@ void ESP8266WiFiGenericClass::_eventCallback(void* arg)
         WiFiClient::stopAll();
     }
 
+    if (event->event == EVENT_STAMODE_AUTHMODE_CHANGE) {
+        auto& src = event->event_info.auth_change;
+        if ((src.old_mode != AUTH_OPEN) && (src.new_mode == AUTH_OPEN)) {
+            // CVE-2020-12638 workaround.  When we get a change to AUTH_OPEN from any other mode, drop the WiFi link because it's a downgrade attack
+            // TODO - When upgrading to 3.x.x with fix, remove this code
+            DEBUG_WIFI("WIFI_EVENT_STAMODE_AUTHMODE_CHANGE from encrypted(%d) to AUTH_OPEN, potential downgrade attack. Reconnecting WiFi. See CVE-2020-12638 for more details\n", src.old_mode);
+            WiFi.reconnect();  // Disconnects from STA and then reconnects
+        }
+    }
+
     for(auto it = std::begin(sCbEventList); it != std::end(sCbEventList); ) {
         WiFiEventHandler &handler = *it;
         if (handler->canExpire() && handler.unique()) {
diff --git a/libraries/ESP8266WiFi/src/WiFiClientSecureBearSSL.cpp b/libraries/ESP8266WiFi/src/WiFiClientSecureBearSSL.cpp
index 773f68cfdc..89621b3671 100644
--- a/libraries/ESP8266WiFi/src/WiFiClientSecureBearSSL.cpp
+++ b/libraries/ESP8266WiFi/src/WiFiClientSecureBearSSL.cpp
@@ -96,11 +96,8 @@ void WiFiClientSecure::_clearAuthenticationSettings() {
   _use_fingerprint = false;
   _use_self_signed = false;
   _knownkey = nullptr;
-  _sk = nullptr;
   _ta = nullptr;
   _axtls_ta = nullptr;
-  _axtls_chain = nullptr;
-  _axtls_sk = nullptr;
 }
 
 
diff --git a/libraries/LittleFS/src/LittleFS.cpp b/libraries/LittleFS/src/LittleFS.cpp
index b85075112e..7fd4351fcb 100644
--- a/libraries/LittleFS/src/LittleFS.cpp
+++ b/libraries/LittleFS/src/LittleFS.cpp
@@ -87,6 +87,7 @@ FileImplPtr LittleFSImpl::open(const char* path, OpenMode openMode, AccessMode a
         // a directory whose name we are carrying around but which cannot be read or written
         return std::make_shared<LittleFSFileImpl>(this, path, nullptr, flags, creation);
     } else if (rc == 0) {
+        lfs_file_sync(&_lfs, fd.get());
         return std::make_shared<LittleFSFileImpl>(this, path, fd, flags, creation);
     } else {
         DEBUGV("LittleFSDirImpl::openFile: rc=%d fd=%p path=`%s` openMode=%d accessMode=%d err=%d\n",
diff --git a/package.json b/package.json
index 5629afd636..235db02b9c 100644
--- a/package.json
+++ b/package.json
@@ -2,5 +2,5 @@
     "name": "framework-arduinoespressif8266",
     "description": "Arduino Wiring-based Framework (ESP8266 Core)",
     "url": "https://github.com/esp8266/Arduino",
-    "version": "2.7.2"
+    "version": "2.7.3"
 }
diff --git a/platform.txt b/platform.txt
index 26d83fa654..2f0e8cb14a 100644
--- a/platform.txt
+++ b/platform.txt
@@ -5,8 +5,8 @@
 # For more info:
 # https://github.com/arduino/Arduino/wiki/Arduino-IDE-1.5-3rd-party-Hardware-specification
 
-name=ESP8266 Boards (2.7.2)
-version=2.7.2
+name=ESP8266 Boards (2.7.3)
+version=2.7.3
 
 # These will be removed by the packager script when doing a JSON release
 runtime.tools.xtensa-lx106-elf-gcc.path={runtime.platform.path}/tools/xtensa-lx106-elf
diff --git a/tests/host/fs/test_fs.inc b/tests/host/fs/test_fs.inc
index 0a2cc423fc..683f3a99ba 100644
--- a/tests/host/fs/test_fs.inc
+++ b/tests/host/fs/test_fs.inc
@@ -198,6 +198,28 @@ TEST_CASE(TESTPRE "seek() pase EOF returns error (#7323)", TESTPAT)
     f.close();
 }
 
+TEST_CASE(TESTPRE "Rewriting file frees space immediately (#7426)", TESTPAT)
+{
+    FS_MOCK_DECLARE(64, 8, 512, "");
+    REQUIRE(FSTYPE.begin());
+    FSInfo inf;
+    FSTYPE.info(inf);
+    // Calculate the size to write per-FS, due to differing overheads
+    int kbToWrite = (inf.totalBytes - inf.usedBytes - 8192) / 1024;
+    // Create and overwrite a file >50% of spaceA (48/64K)
+    for (auto x = 0; x < 2; x++) {
+        auto f = FSTYPE.open("/file1.bin", "w");
+        REQUIRE(f);
+        uint8_t buff[1024];
+        memset(buff, 0xaa, 1024);
+        for (auto i = 0; i < kbToWrite; i++) {
+            REQUIRE(f.write(buff, 1024));
+        }
+        f.close();
+        FSTYPE.info(inf);
+    }
+}
+
 #ifdef FS_HAS_DIRS
 
 #if FSTYPE != SDFS
diff --git a/tools/boards.txt.py b/tools/boards.txt.py
index 8263191495..30f2a9bbe5 100755
--- a/tools/boards.txt.py
+++ b/tools/boards.txt.py
@@ -759,8 +759,9 @@
             },
         'macro': [
             'resetmethod_nodemcu',
-            'flashmode_dio',
+            'flashmode_menu',
             'flashfreq_80',
+            '2M',
             '512K',
             ],
         'desc': [ 'gen4-IoD Range of ESP8266 powered Display Modules by 4D Systems.',
@@ -771,7 +772,7 @@
                   '',
                   'The gen4-IoD range can be programmed using the Arduino IDE and also the 4D Systems Workshop4 IDE, which incorporates many additional graphics benefits. GFX4d library is available, along with a number of demo applications.',
                   '',
-                  '- Product page: http://www.4dsystems.com.au/product/gen4-IoD',
+                  '- Product page: https://4dsystems.com.au/products/iot-display-modules',
                   ],
     }),
     ( 'oak', {