diff --git a/data/update.html b/data/update.html
index 08844730..f387c53d 100644
--- a/data/update.html
+++ b/data/update.html
@@ -59,7 +59,7 @@ <h1 class="mt-5">Update</h1>
 
                     <div class="tab-pane fade active show" id="update" role="tabpanel" aria-labelledby="update-tab">
                         <br />
-                        <p>Upload <u>~FIRMWARE_FILENAME~</u> file for software update or <u>~FILESYSTEM_FILENAME~</u> for updating the filesystem.</p>
+                        <p>Upload <u>~FIRMWARE_FILENAME~</u> and <u>~BOOTLOADER_FILENAME~</u> file for software update or <u>~FILESYSTEM_FILENAME~</u> for updating the filesystem.</p>
                         <p>Use multi-select to upload both at once.</p>
                         <div class="input-group">
                             <div class="custom-file">
@@ -169,6 +169,7 @@ <h1 class="mt-5">Update</h1>
                     file = document.getElementById("inputFile").files[index];
 
                     if (("~FIRMWARE_FILENAME~" === file.name) ||
+                        ("~BOOTLOADER_FILENAME~" === file.name) ||
                         ("~FILESYSTEM_FILENAME~" === file.name)) {
 
                         files.push(file);
@@ -190,6 +191,8 @@ <h1 class="mt-5">Update</h1>
 
                         if ("~FIRMWARE_FILENAME~" === files[index].name) {
                             fileHeaders["X-File-Size-Firmware"] = files[index].size;
+                        } else if ("~BOOTLOADER_FILENAME~" === files[index].name) {
+                            fileHeaders["X-File-Size-Bootloader"] = files[index].size;
                         } else if ("~FILESYSTEM_FILENAME~" === files[index].name) {
                             fileHeaders["X-File-Size-Filesystem"] = files[index].size;
                         }
diff --git a/src/Web/Pages.cpp b/src/Web/Pages.cpp
index e91c4041..98fa409d 100644
--- a/src/Web/Pages.cpp
+++ b/src/Web/Pages.cpp
@@ -109,6 +109,9 @@ namespace tmpl
 /** Firmware binary filename, used for update. */
 static const char*      FIRMWARE_FILENAME               = "firmware.bin";
 
+/** Bootloader binary filename, used for update. */
+static const char*      BOOTLOADER_FILENAME             = "bootloader.bin";
+
 /** Path to the plugin webpages. */
 static const String     PLUGIN_PAGE_PATH                = "/plugins/";
 
@@ -125,6 +128,7 @@ static bool             gIsUploadError                  = false;
 static TmplKeyWordFunc  gTmplKeyWordToFunc[]            =
 {
     "ARDUINO_IDF_BRANCH",   []() -> String { return CONFIG_ARDUINO_IDF_BRANCH; },
+    "BOOTLOADER_FILENAME",  []() -> String { return BOOTLOADER_FILENAME; },
     "ESP_CHIP_ID",          tmpl::getEspChipId,
     "ESP_CHIP_REV",         []() -> String { return String(ESP.getChipRevision()); },
     "ESP_CPU_FREQ",         []() -> String { return String(ESP.getCpuFreqMHz()); },
@@ -491,30 +495,36 @@ static void uploadHandler(AsyncWebServerRequest *request, const String& filename
             LOG_WARNING("Pending upload aborted.");
         }
 
-        /* Upload firmware or filesystem? */
-        int cmd = (filename == FILESYSTEM_FILENAME) ? U_SPIFFS : U_FLASH;
-
-        if (U_FLASH == cmd)
+        /* Upload firmware, bootloader or filesystem? */
+        int             cmd             = U_FLASH;
+        AsyncWebHeader* headerXFileSize = nullptr;
+        
+        if (filename == FIRMWARE_FILENAME)
         {
-            AsyncWebHeader* headerXFileSizeFirmware = request->getHeader("X-File-Size-Firmware");
-
-            /* Firmware file size available? */
-            if (nullptr != headerXFileSizeFirmware)
-            {
-                /* If conversion fails, it will contain UPDATE_SIZE_UNKNOWN. */
-                (void)Util::strToUInt32(headerXFileSizeFirmware->value(), fileSize);
-            }
+            cmd = U_FLASH;
+            headerXFileSize = request->getHeader("X-File-Size-Firmware");
+        }
+        else if (filename == BOOTLOADER_FILENAME)
+        {
+            cmd = U_FLASH;
+            headerXFileSize = request->getHeader("X-File-Size-Bootloader");
         }
-        else if (U_SPIFFS == cmd)
+        else if (filename == FILESYSTEM_FILENAME)
         {
-            AsyncWebHeader* headerXFileSizeFilesystem = request->getHeader("X-File-Size-Filesystem");
+            cmd = U_SPIFFS;
+            headerXFileSize = request->getHeader("X-File-Size-Filesystem");
+        }
+        else
+        {
+            /* Unknown. */
+            ;
+        }
 
-            /* Firmware file size available? */
-            if (nullptr != headerXFileSizeFilesystem)
-            {
-                /* If conversion fails, it will contain UPDATE_SIZE_UNKNOWN. */
-                (void)Util::strToUInt32(headerXFileSizeFilesystem->value(), fileSize);
-            }
+        /* File size available? */
+        if (nullptr != headerXFileSize)
+        {
+            /* If conversion fails, it will contain UPDATE_SIZE_UNKNOWN. */
+            (void)Util::strToUInt32(headerXFileSize->value(), fileSize);
         }
 
         if (UPDATE_SIZE_UNKNOWN == fileSize)