diff --git a/os/emscripten/pre.js b/os/emscripten/pre.js
index 68e76678aa..8e46ae3460 100644
--- a/os/emscripten/pre.js
+++ b/os/emscripten/pre.js
@@ -30,24 +30,6 @@ Module.preRun.push(function() {
 
     Module.addRunDependency('syncfs');
     FS.syncfs(true, function (err) {
-        /* FS.mkdir() tends to fail if parent folders do not exist. */
-        if (!FS.analyzePath(content_download_dir).exists) {
-            FS.mkdir(content_download_dir);
-        }
-        if (!FS.analyzePath(content_download_dir + '/baseset').exists) {
-            FS.mkdir(content_download_dir + '/baseset');
-        }
-
-        /* Check if the OpenGFX baseset is already downloaded. */
-        if (!FS.analyzePath(content_download_dir + '/baseset/opengfx-0.6.0.tar').exists) {
-            window.openttd_downloaded_opengfx = true;
-            FS.createPreloadedFile(content_download_dir + '/baseset', 'opengfx-0.6.0.tar', 'https://binaries.openttd.org/installer/emscripten/opengfx-0.6.0.tar', true, true);
-        } else {
-            /* Fake dependency increase, so the counter is stable. */
-            Module.addRunDependency('opengfx');
-            Module.removeRunDependency('opengfx');
-        }
-
         Module.removeRunDependency('syncfs');
     });
 
@@ -74,6 +56,23 @@ Module.preRun.push(function() {
         window.openttd_syncfs(Module.onAbort);
     }
 
+    window.openttd_bootstrap = function(current, total) {
+        Module.onBootstrap(current, total);
+    }
+
+    window.openttd_bootstrap_failed = function() {
+        Module.onBootstrapFailed();
+    }
+
+    window.openttd_bootstrap_reload = function() {
+        window.openttd_syncfs(function() {
+            Module.onBootstrapReload();
+            setTimeout(function() {
+                location.reload();
+            }, 1000);
+        });
+    }
+
     window.openttd_server_list = function() {
         add_server = Module.cwrap("em_openttd_add_server", null, ["string"]);
 
@@ -125,11 +124,3 @@ Module.preRun.push(function() {
        return ret;
    }
 });
-
-Module.postRun.push(function() {
-    /* Check if we downloaded OpenGFX; if so, sync the virtual FS back to the
-     * IDBFS so OpenGFX is stored persistent. */
-    if (window['openttd_downloaded_opengfx']) {
-        FS.syncfs(false, function (err) { });
-    }
-});
diff --git a/os/emscripten/shell.html b/os/emscripten/shell.html
index af031c6df8..21f720e7e4 100644
--- a/os/emscripten/shell.html
+++ b/os/emscripten/shell.html
@@ -75,7 +75,6 @@
       }
       #message {
         color: #101010;
-        height: 54px;
         padding: 4px 4px;
       }
 
@@ -144,6 +143,8 @@
         })(),
 
         setStatus: function(text) {
+          if (document.getElementById("canvas").style.display == "none") return;
+
           var m = text.match(/^([^(]+)\((\d+(\.\d+)?)\/(\d+)\)$/);
 
           if (m) {
@@ -171,6 +172,27 @@
           document.getElementById("message").innerHTML = "Preparing game ...";
         },
 
+        onBootstrap: function(current, total) {
+          document.getElementById("canvas").style.display = "none";
+
+          document.getElementById("title").innerHTML = "Missing base graphics";
+          document.getElementById("message").innerHTML = "OpenTTD is downloading base graphics.<br/><br/>" + current + " / " + total + " bytes downloaded.";
+        },
+
+        onBootstrapFailed: function(current, total) {
+          document.getElementById("canvas").style.display = "none";
+
+          document.getElementById("title").innerHTML = "Missing base graphics";
+          document.getElementById("message").innerHTML = "Failed to download base graphics.<br/>The game cannot start without base graphics.<br/><br/>Please check your Internet connection and/or the console log.<br/>Reload your browser to try again.";
+        },
+
+        onBootstrapReload: function() {
+          document.getElementById("canvas").style.display = "none";
+
+          document.getElementById("title").innerHTML = "Missing base graphics";
+          document.getElementById("message").innerHTML = "Downloading base graphics done.<br/><br/>Your browser will reload to start the game.";
+        },
+
         onExit: function() {
           document.getElementById("canvas").style.display = "none";
 
diff --git a/src/bootstrap_gui.cpp b/src/bootstrap_gui.cpp
index 57d7e96fd2..063e908a32 100644
--- a/src/bootstrap_gui.cpp
+++ b/src/bootstrap_gui.cpp
@@ -286,6 +286,76 @@ public:
 
 #endif /* defined(WITH_FREETYPE) */
 
+#if defined(__EMSCRIPTEN__)
+#	include <emscripten.h>
+#	include "network/network.h"
+#	include "network/network_content.h"
+#	include "openttd.h"
+#	include "video/video_driver.hpp"
+
+class BootstrapEmscripten : public ContentCallback {
+	bool downloading{false};
+	uint total_files{0};
+	uint total_bytes{0};
+	uint downloaded_bytes{0};
+
+public:
+	BootstrapEmscripten()
+	{
+		_network_content_client.AddCallback(this);
+		_network_content_client.Connect();
+	}
+
+	~BootstrapEmscripten()
+	{
+		_network_content_client.RemoveCallback(this);
+	}
+
+	void OnConnect(bool success) override
+	{
+		if (!success) {
+			EM_ASM({ if (window["openttd_bootstrap_failed"]) openttd_bootstrap_failed(); });
+			return;
+		}
+
+		/* Once connected, request the metadata. */
+		_network_content_client.RequestContentList(CONTENT_TYPE_BASE_GRAPHICS);
+	}
+
+	void OnReceiveContentInfo(const ContentInfo *ci) override
+	{
+		if (this->downloading) return;
+
+		/* And once the metadata is received, start downloading it. */
+		_network_content_client.Select(ci->id);
+		_network_content_client.DownloadSelectedContent(this->total_files, this->total_bytes);
+		this->downloading = true;
+
+		EM_ASM({ if (window["openttd_bootstrap"]) openttd_bootstrap($0, $1); }, this->downloaded_bytes, this->total_bytes);
+	}
+
+	void OnDownloadProgress(const ContentInfo *ci, int bytes) override
+	{
+		/* A negative value means we are resetting; for example, when retrying or using a fallback. */
+		if (bytes < 0) {
+			this->downloaded_bytes = 0;
+		} else {
+			this->downloaded_bytes += bytes;
+		}
+
+		EM_ASM({ if (window["openttd_bootstrap"]) openttd_bootstrap($0, $1); }, this->downloaded_bytes, this->total_bytes);
+	}
+
+	void OnDownloadComplete(ContentID cid) override
+	{
+		/* _exit_game is used to break out of the outer video driver's MainLoop. */
+		_exit_game = true;
+
+		delete this;
+	}
+};
+#endif /* __EMSCRIPTEN__ */
+
 /**
  * Handle all procedures for bootstrapping OpenTTD without a base graphics set.
  * This requires all kinds of trickery that is needed to avoid the use of
@@ -300,12 +370,15 @@ bool HandleBootstrap()
 	if (BlitterFactory::GetCurrentBlitter()->GetScreenDepth() == 0) goto failure;
 
 	/* If there is no network or no non-sprite font, then there is nothing we can do. Go straight to failure. */
-#if (defined(_WIN32) && defined(WITH_UNISCRIBE)) || (defined(WITH_FREETYPE) && (defined(WITH_FONTCONFIG) || defined(__APPLE__))) || defined(WITH_COCOA)
+#if defined(__EMSCRIPTEN__) || (defined(_WIN32) && defined(WITH_UNISCRIBE)) || (defined(WITH_FREETYPE) && (defined(WITH_FONTCONFIG) || defined(__APPLE__))) || defined(WITH_COCOA)
 	if (!_network_available) goto failure;
 
 	/* First tell the game we're bootstrapping. */
 	_game_mode = GM_BOOTSTRAP;
 
+#if defined(__EMSCRIPTEN__)
+	new BootstrapEmscripten();
+#else
 	/* Initialise the font cache. */
 	InitializeUnicodeGlyphMap();
 	/* Next "force" finding a suitable non-sprite font as the local font is missing. */
@@ -324,6 +397,7 @@ bool HandleBootstrap()
 	/* Finally ask the question. */
 	new BootstrapBackground();
 	new BootstrapAskForDownloadWindow();
+#endif /* __EMSCRIPTEN__ */
 
 	/* Process the user events. */
 	VideoDriver::GetInstance()->MainLoop();
diff --git a/src/video/sdl2_v.cpp b/src/video/sdl2_v.cpp
index 1f18d143fd..183b8354c1 100644
--- a/src/video/sdl2_v.cpp
+++ b/src/video/sdl2_v.cpp
@@ -615,7 +615,11 @@ void VideoDriver_SDL_Base::LoopOnce()
 		/* In effect, the game ends here. As emscripten_set_main_loop() caused
 		 * the stack to be unwound, the code after MainLoop() in
 		 * openttd_main() is never executed. */
-		EM_ASM(if (window["openttd_exit"]) openttd_exit());
+		if (_game_mode == GM_BOOTSTRAP) {
+			EM_ASM(if (window["openttd_bootstrap_reload"]) openttd_bootstrap_reload());
+		} else {
+			EM_ASM(if (window["openttd_exit"]) openttd_exit());
+		}
 #endif
 		return;
 	}