diff --git a/drivers/gles3/rasterizer_canvas_gles3.cpp b/drivers/gles3/rasterizer_canvas_gles3.cpp
index 5fabeb94f5b..941b1a1b280 100644
--- a/drivers/gles3/rasterizer_canvas_gles3.cpp
+++ b/drivers/gles3/rasterizer_canvas_gles3.cpp
@@ -2742,8 +2742,7 @@ RasterizerCanvasGLES3::RasterizerCanvasGLES3() {
 		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
 	}
 
-	int uniform_max_size = config->max_uniform_buffer_size;
-	if (uniform_max_size < 65536) {
+	if (config->max_uniform_buffer_size < 65536) {
 		data.max_lights_per_render = 64;
 	} else {
 		data.max_lights_per_render = 256;
diff --git a/drivers/gles3/rasterizer_gles3.cpp b/drivers/gles3/rasterizer_gles3.cpp
index 993197e371c..60891b8b4e1 100644
--- a/drivers/gles3/rasterizer_gles3.cpp
+++ b/drivers/gles3/rasterizer_gles3.cpp
@@ -398,8 +398,7 @@ void RasterizerGLES3::_blit_render_target_to_screen(RID p_render_target, Display
 			// Viewport doesn't cover entire window so clear window to black before blitting.
 			// Querying the actual window size from the DisplayServer would deadlock in separate render thread mode,
 			// so let's set the biggest viewport the implementation supports, to be sure the window is fully covered.
-			GLsizei max_vp[2] = {};
-			glGetIntegerv(GL_MAX_VIEWPORT_DIMS, max_vp);
+			Size2i max_vp = GLES3::Utilities::get_singleton()->get_maximum_viewport_size();
 			glViewport(0, 0, max_vp[0], max_vp[1]);
 			glClearColor(0.0, 0.0, 0.0, 1.0);
 			glClear(GL_COLOR_BUFFER_BIT);
diff --git a/drivers/gles3/shader_gles3.cpp b/drivers/gles3/shader_gles3.cpp
index 876309d22c5..4a15ed827a0 100644
--- a/drivers/gles3/shader_gles3.cpp
+++ b/drivers/gles3/shader_gles3.cpp
@@ -37,6 +37,7 @@
 #include "core/io/file_access.h"
 
 #include "drivers/gles3/rasterizer_gles3.h"
+#include "drivers/gles3/storage/config.h"
 
 static String _mkid(const String &p_id) {
 	String id = "m_" + p_id.replace("__", "_dus_");
@@ -801,7 +802,9 @@ void ShaderGLES3::initialize(const String &p_general_defines, int p_base_texture
 		print_verbose("Shader '" + name + "' SHA256: " + base_sha256);
 	}
 
-	glGetInteger64v(GL_MAX_TEXTURE_IMAGE_UNITS, &max_image_units);
+	GLES3::Config *config = GLES3::Config::get_singleton();
+	ERR_FAIL_NULL(config);
+	max_image_units = config->max_texture_image_units;
 }
 
 void ShaderGLES3::set_shader_cache_dir(const String &p_dir) {
diff --git a/drivers/gles3/shader_gles3.h b/drivers/gles3/shader_gles3.h
index 8968e76c12c..9ee939e3439 100644
--- a/drivers/gles3/shader_gles3.h
+++ b/drivers/gles3/shader_gles3.h
@@ -148,7 +148,7 @@ private:
 	static bool shader_cache_save_debug;
 	bool shader_cache_dir_valid = false;
 
-	int64_t max_image_units = 0;
+	GLint max_image_units = 0;
 
 	enum StageType {
 		STAGE_TYPE_VERTEX,
diff --git a/drivers/gles3/storage/config.cpp b/drivers/gles3/storage/config.cpp
index 6b5e2277826..2ab1ef1c9d4 100644
--- a/drivers/gles3/storage/config.cpp
+++ b/drivers/gles3/storage/config.cpp
@@ -45,9 +45,9 @@ Config::Config() {
 	singleton = this;
 
 	{
-		int64_t max_extensions = 0;
-		glGetInteger64v(GL_NUM_EXTENSIONS, &max_extensions);
-		for (int64_t i = 0; i < max_extensions; i++) {
+		GLint max_extensions = 0;
+		glGetIntegerv(GL_NUM_EXTENSIONS, &max_extensions);
+		for (int i = 0; i < max_extensions; i++) {
 			const GLubyte *s = glGetStringi(GL_EXTENSIONS, i);
 			if (!s) {
 				break;
@@ -80,11 +80,14 @@ Config::Config() {
 		rgtc_supported = extensions.has("GL_EXT_texture_compression_rgtc") || extensions.has("GL_ARB_texture_compression_rgtc") || extensions.has("EXT_texture_compression_rgtc");
 	}
 
-	glGetInteger64v(GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS, &max_vertex_texture_image_units);
-	glGetInteger64v(GL_MAX_TEXTURE_IMAGE_UNITS, &max_texture_image_units);
-	glGetInteger64v(GL_MAX_TEXTURE_SIZE, &max_texture_size);
+	glGetIntegerv(GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS, &max_vertex_texture_image_units);
+	glGetIntegerv(GL_MAX_TEXTURE_IMAGE_UNITS, &max_texture_image_units);
+	glGetIntegerv(GL_MAX_TEXTURE_SIZE, &max_texture_size);
+	glGetIntegerv(GL_MAX_VIEWPORT_DIMS, max_viewport_size);
 	glGetInteger64v(GL_MAX_UNIFORM_BLOCK_SIZE, &max_uniform_buffer_size);
-	glGetInteger64v(GL_MAX_VIEWPORT_DIMS, max_viewport_size);
+
+	// sanity clamp buffer size to 16K..1MB
+	max_uniform_buffer_size = CLAMP(max_uniform_buffer_size, 16384, 1048576);
 
 	support_anisotropic_filter = extensions.has("GL_EXT_texture_filter_anisotropic");
 	if (support_anisotropic_filter) {
diff --git a/drivers/gles3/storage/config.h b/drivers/gles3/storage/config.h
index c3ab65f0bc0..1ff80d9a9e8 100644
--- a/drivers/gles3/storage/config.h
+++ b/drivers/gles3/storage/config.h
@@ -57,11 +57,12 @@ public:
 	bool use_nearest_mip_filter = false;
 	bool use_depth_prepass = true;
 
-	int64_t max_vertex_texture_image_units = 0;
-	int64_t max_texture_image_units = 0;
-	int64_t max_texture_size = 0;
-	int64_t max_viewport_size[2] = { 0, 0 };
-	int64_t max_uniform_buffer_size = 0;
+	GLint max_vertex_texture_image_units = 0;
+	GLint max_texture_image_units = 0;
+	GLint max_texture_size = 0;
+	GLint max_viewport_size[2] = { 0, 0 };
+	GLint64 max_uniform_buffer_size = 0;
+
 	int64_t max_renderable_elements = 0;
 	int64_t max_renderable_lights = 0;
 	int64_t max_lights_per_object = 0;
diff --git a/drivers/gles3/storage/utilities.cpp b/drivers/gles3/storage/utilities.cpp
index 356dc06733b..7f0be364663 100644
--- a/drivers/gles3/storage/utilities.cpp
+++ b/drivers/gles3/storage/utilities.cpp
@@ -463,10 +463,7 @@ String Utilities::get_video_adapter_api_version() const {
 
 Size2i Utilities::get_maximum_viewport_size() const {
 	Config *config = Config::get_singleton();
-	if (!config) {
-		return Size2i();
-	}
-
+	ERR_FAIL_NULL_V(config, Size2i());
 	return Size2i(config->max_viewport_size[0], config->max_viewport_size[1]);
 }