diff --git a/package/ci/circleci.yml b/package/ci/circleci.yml
index c5e5ac267d..10db1a0182 100644
--- a/package/ci/circleci.yml
+++ b/package/ci/circleci.yml
@@ -19,7 +19,7 @@ executors:
   xcode-11_6:
     macos:
       xcode: 11.6.0
-  emscripten:
+  emscripten1:
     docker:
     # 1.39.0 is the oldest on Docker. Anything before 1.39.2 is useless as emar
     # randomly asserts: https://github.com/emscripten-core/emscripten/pull/9742
@@ -28,6 +28,12 @@ executors:
     # https://github.com/mosra/magnum/issues/413,
     # https://github.com/emscripten-core/emscripten/pull/10161
     - image: emscripten/emsdk:1.39.6-upstream
+  emscripten2:
+    docker:
+    # Used by the webgl2 job. First version that exposes glGetBufferSubData()
+    # so GLES3 tests can read buffer data without having to check the
+    # Emscripten version.
+    - image: emscripten/emsdk:2.0.17
   android-29:
     machine:
       image: android:202102-01
@@ -512,7 +518,7 @@ jobs:
     - lcov
 
   emscripten-webgl1:
-    executor: emscripten
+    executor: emscripten1
     environment:
       # STUPID yml interprets unquoted ON as a boolean
       TARGET_GLES2: "ON"
@@ -523,7 +529,7 @@ jobs:
         script: emscripten.sh
 
   emscripten-webgl2:
-    executor: emscripten
+    executor: emscripten2
     environment:
       # STUPID yml interprets unquoted OFF as a boolean
       TARGET_GLES2: "OFF"
diff --git a/src/Magnum/DebugTools/BufferData.h b/src/Magnum/DebugTools/BufferData.h
index ada62a5ed0..8fa8af909b 100644
--- a/src/Magnum/DebugTools/BufferData.h
+++ b/src/Magnum/DebugTools/BufferData.h
@@ -25,7 +25,7 @@
     DEALINGS IN THE SOFTWARE.
 */
 
-#if defined(MAGNUM_TARGET_GL) && !defined(MAGNUM_TARGET_WEBGL)
+#if defined(MAGNUM_TARGET_GL) && !(defined(MAGNUM_TARGET_WEBGL) && defined(MAGNUM_TARGET_GLES2))
 /** @file
  * @brief Function @ref Magnum::DebugTools::bufferData(), @ref Magnum::DebugTools::bufferSubData()
  */
@@ -36,7 +36,7 @@
 #include "Magnum/GL/Buffer.h"
 #include "Magnum/DebugTools/visibility.h"
 
-#if defined(MAGNUM_TARGET_GL) && !defined(MAGNUM_TARGET_WEBGL)
+#if defined(MAGNUM_TARGET_GL) && !(defined(MAGNUM_TARGET_WEBGL) && defined(MAGNUM_TARGET_GLES2))
 namespace Magnum { namespace DebugTools {
 
 namespace Implementation {
@@ -47,7 +47,8 @@ namespace Implementation {
 @brief Buffer subdata
 
 Emulates @ref GL::Buffer::subData() call on platforms that don't support it
-(such as OpenGL ES) by using @ref GL::Buffer::map().
+(such as OpenGL ES) by using @ref GL::Buffer::mapRead(). On desktop GL and
+WebGL 2.0 it's just an alias to @ref GL::Buffer::subData().
 
 @note This function is available only if Magnum is compiled with
     @ref MAGNUM_TARGET_GL "TARGET_GL" enabled (done by default). See
@@ -55,19 +56,28 @@ Emulates @ref GL::Buffer::subData() call on platforms that don't support it
 
 @requires_gles30 Extension @gl_extension{EXT,map_buffer_range} in OpenGL ES
     2.0.
-@requires_gles Buffer mapping is not available in WebGL.
+@requires_webgl20 Buffer data queries or buffer mapping are not available in
+    WebGL 1.0.
 */
-template<class T> Containers::Array<T> inline bufferSubData(GL::Buffer& buffer, GLintptr offset, GLsizeiptr size) {
+template<class T = char> Containers::Array<T> inline bufferSubData(GL::Buffer& buffer, GLintptr offset, GLsizeiptr size) {
+    if(!size) return {};
+    #if !defined(MAGNUM_TARGET_GLES) || defined(MAGNUM_TARGET_WEBGL)
+    Containers::Array<char> data = buffer.subData(offset, size*sizeof(T));
+    CORRADE_INTERNAL_ASSERT(!data.deleter());
+    return Containers::Array<T>{reinterpret_cast<T*>(data.release()), std::size_t(size)};
+    #else
     Containers::Array<T> data{std::size_t(size)};
-    if(size) Implementation::bufferSubData(buffer, offset, size*sizeof(T), data);
+    Implementation::bufferSubData(buffer, offset, size*sizeof(T), data);
     return data;
+    #endif
 }
 
 /**
 @brief Buffer data
 
 Emulates @ref GL::Buffer::data() call on platforms that don't support it (such
-as OpenGL ES) by using @ref GL::Buffer::map().
+as OpenGL ES) by using @ref GL::Buffer::mapRead(). On desktop GL and WebGL 2.0
+it's just an alias to @ref GL::Buffer::data().
 
 @note This function is available only if Magnum is compiled with
     @ref MAGNUM_TARGET_GL "TARGET_GL" enabled (done by default). See
@@ -75,7 +85,8 @@ as OpenGL ES) by using @ref GL::Buffer::map().
 
 @requires_gles30 Extension @gl_extension{EXT,map_buffer_range} in OpenGL ES
     2.0.
-@requires_gles Buffer mapping is not available in WebGL.
+@requires_webgl20 Buffer data queries or buffer mapping are not available in
+    WebGL 1.0.
 */
 template<class T = char> Containers::Array<T> inline bufferData(GL::Buffer& buffer) {
     const Int bufferSize = buffer.size();
@@ -85,7 +96,7 @@ template<class T = char> Containers::Array<T> inline bufferData(GL::Buffer& buff
 
 }}
 #else
-#error this header is available only in the OpenGL (ES) build and not available in the WebGL build
+#error this header is not available in the WebGL 1.0 build
 #endif
 
 #endif
diff --git a/src/Magnum/DebugTools/CMakeLists.txt b/src/Magnum/DebugTools/CMakeLists.txt
index f8ddeadfee..2618fbab73 100644
--- a/src/Magnum/DebugTools/CMakeLists.txt
+++ b/src/Magnum/DebugTools/CMakeLists.txt
@@ -72,7 +72,7 @@ if(TARGET_GL)
         endif()
     endif()
 
-    if(NOT MAGNUM_TARGET_WEBGL)
+    if(NOT (MAGNUM_TARGET_WEBGL AND MAGNUM_TARGET_GLES2))
         list(APPEND MagnumDebugTools_SRCS
             BufferData.cpp)
 
diff --git a/src/Magnum/DebugTools/Test/BufferDataGLTest.cpp b/src/Magnum/DebugTools/Test/BufferDataGLTest.cpp
index 6b2871e59d..b697e69f0b 100644
--- a/src/Magnum/DebugTools/Test/BufferDataGLTest.cpp
+++ b/src/Magnum/DebugTools/Test/BufferDataGLTest.cpp
@@ -47,37 +47,51 @@ BufferDataGLTest::BufferDataGLTest() {
 constexpr Int Data[] = {2, 7, 5, 13, 25};
 
 void BufferDataGLTest::data() {
-    #ifndef MAGNUM_TARGET_GLES
-    if(!GL::Context::current().isExtensionSupported<GL::Extensions::ARB::map_buffer_range>())
-        CORRADE_SKIP(GL::Extensions::ARB::map_buffer_range::string() << "is not supported.");
-    #elif defined(MAGNUM_TARGET_GLES2)
+    #ifdef MAGNUM_TARGET_GLES2
     if(!GL::Context::current().isExtensionSupported<GL::Extensions::EXT::map_buffer_range>())
         CORRADE_SKIP(GL::Extensions::EXT::map_buffer_range::string() << "is not supported.");
     #endif
 
     GL::Buffer buffer;
+
+    const Containers::Array<Int> emptyContents = bufferData<Int>(buffer);
+    MAGNUM_VERIFY_NO_GL_ERROR();
+    CORRADE_VERIFY(emptyContents.isEmpty());
+
     buffer.setData(Data, GL::BufferUsage::StaticDraw);
-    const Containers::Array<Int> contents = bufferData<Int>(buffer);
+
+    const Containers::Array<char> contents = bufferData(buffer);
+    MAGNUM_VERIFY_NO_GL_ERROR();
+    CORRADE_COMPARE_AS(contents,
+        Containers::arrayCast<const char>(Containers::arrayView(Data)),
+        TestSuite::Compare::Container);
+    const Containers::Array<Int> intContents = bufferData<Int>(buffer);
     MAGNUM_VERIFY_NO_GL_ERROR();
-    CORRADE_COMPARE_AS(contents, Containers::arrayView(Data),
+    CORRADE_COMPARE_AS(intContents, Containers::arrayView(Data),
         TestSuite::Compare::Container);
 }
 
 void BufferDataGLTest::subData() {
-    #ifndef MAGNUM_TARGET_GLES
-    if(!GL::Context::current().isExtensionSupported<GL::Extensions::ARB::map_buffer_range>())
-        CORRADE_SKIP(GL::Extensions::ARB::map_buffer_range::string() << "is not supported.");
-    #elif defined(MAGNUM_TARGET_GLES2)
+    #ifdef MAGNUM_TARGET_GLES2
     if(!GL::Context::current().isExtensionSupported<GL::Extensions::EXT::map_buffer_range>())
         CORRADE_SKIP(GL::Extensions::EXT::map_buffer_range::string() << "is not supported.");
     #endif
 
     GL::Buffer buffer;
     buffer.setData(Data, GL::BufferUsage::StaticDraw);
-    const Containers::Array<Int> contents = bufferSubData<Int>(buffer, 4, 3);
+
+    const Containers::Array<char> contents = bufferSubData(buffer, 4, 3*4);
     MAGNUM_VERIFY_NO_GL_ERROR();
-    CORRADE_COMPARE_AS(contents, Containers::arrayView(Data).slice(1, 4),
+    CORRADE_COMPARE_AS(contents,
+        Containers::arrayCast<const char>(Containers::arrayView(Data).slice(1, 4)),
         TestSuite::Compare::Container);
+    const Containers::Array<Int> intContents = bufferSubData<Int>(buffer, 4, 3);
+    MAGNUM_VERIFY_NO_GL_ERROR();
+    CORRADE_COMPARE_AS(intContents, Containers::arrayView(Data).slice(1, 4),
+        TestSuite::Compare::Container);
+    const Containers::Array<Int> emptyContents = bufferSubData<Int>(buffer, 4, 0);
+    MAGNUM_VERIFY_NO_GL_ERROR();
+    CORRADE_VERIFY(emptyContents.isEmpty());
 }
 
 }}}}
diff --git a/src/Magnum/DebugTools/Test/CMakeLists.txt b/src/Magnum/DebugTools/Test/CMakeLists.txt
index f71ed0a358..290695b4e4 100644
--- a/src/Magnum/DebugTools/Test/CMakeLists.txt
+++ b/src/Magnum/DebugTools/Test/CMakeLists.txt
@@ -118,7 +118,7 @@ if(TARGET_GL)
         corrade_add_test(DebugToolsTextureImageGLTest TextureImageGLTest.cpp
             LIBRARIES MagnumDebugTools MagnumOpenGLTester)
 
-        if(NOT MAGNUM_TARGET_WEBGL)
+        if(NOT (MAGNUM_TARGET_WEBGL AND MAGNUM_TARGET_GLES2))
             corrade_add_test(DebugToolsBufferDataGLTest BufferDataGLTest.cpp
                 LIBRARIES MagnumDebugTools MagnumOpenGLTester)
         endif()
diff --git a/src/Magnum/GL/Buffer.cpp b/src/Magnum/GL/Buffer.cpp
index b3b544cda6..d839f4fd75 100644
--- a/src/Magnum/GL/Buffer.cpp
+++ b/src/Magnum/GL/Buffer.cpp
@@ -329,7 +329,7 @@ Int Buffer::size() {
     return size;
 }
 
-#ifndef MAGNUM_TARGET_GLES
+#if !defined(MAGNUM_TARGET_GLES) || (defined(MAGNUM_TARGET_WEBGL) && !defined(MAGNUM_TARGET_GLES2) && __EMSCRIPTEN_major__*10000 + __EMSCRIPTEN_minor__*100 + __EMSCRIPTEN_tiny__ >= 20017)
 Containers::Array<char> Buffer::data() {
     return subData(0, size());
 }
@@ -372,7 +372,7 @@ Buffer& Buffer::flushMappedRange(const GLintptr offset, const GLsizeiptr length)
 bool Buffer::unmap() { return (this->*Context::current().state().buffer.unmapImplementation)(); }
 #endif
 
-#ifndef MAGNUM_TARGET_GLES
+#if !defined(MAGNUM_TARGET_GLES) || (defined(MAGNUM_TARGET_WEBGL) && !defined(MAGNUM_TARGET_GLES2) && __EMSCRIPTEN_major__*10000 + __EMSCRIPTEN_minor__*100 + __EMSCRIPTEN_tiny__ >= 20017)
 Containers::Array<char> Buffer::subData(const GLintptr offset, const GLsizeiptr size) {
     Containers::Array<char> data(size);
     if(size) (this->*Context::current().state().buffer.getSubDataImplementation)(offset, size, data);
@@ -468,11 +468,13 @@ void Buffer::getParameterImplementationDSA(const GLenum value, GLint* const data
 }
 #endif
 
-#ifndef MAGNUM_TARGET_GLES
+#if !defined(MAGNUM_TARGET_GLES) || (defined(MAGNUM_TARGET_WEBGL) && !defined(MAGNUM_TARGET_GLES2) && __EMSCRIPTEN_major__*10000 + __EMSCRIPTEN_minor__*100 + __EMSCRIPTEN_tiny__ >= 20017)
 void Buffer::getSubDataImplementationDefault(const GLintptr offset, const GLsizeiptr size, GLvoid* const data) {
     glGetBufferSubData(GLenum(bindSomewhereInternal(_targetHint)), offset, size, data);
 }
+#endif
 
+#ifndef MAGNUM_TARGET_GLES
 void Buffer::getSubDataImplementationDSA(const GLintptr offset, const GLsizeiptr size, GLvoid* const data) {
     glGetNamedBufferSubData(_id, offset, size, data);
 }
diff --git a/src/Magnum/GL/Buffer.h b/src/Magnum/GL/Buffer.h
index 076626f502..b88178298b 100644
--- a/src/Magnum/GL/Buffer.h
+++ b/src/Magnum/GL/Buffer.h
@@ -1089,7 +1089,7 @@ class MAGNUM_GL_EXPORT Buffer: public AbstractObject {
          */
         Int size();
 
-        #ifndef MAGNUM_TARGET_GLES
+        #if !defined(MAGNUM_TARGET_GLES) || (defined(MAGNUM_TARGET_WEBGL) && !defined(MAGNUM_TARGET_GLES2) && __EMSCRIPTEN_major__*10000 + __EMSCRIPTEN_minor__*100 + __EMSCRIPTEN_tiny__ >= 20017)
         /**
          * @brief Buffer data
          *
@@ -1101,9 +1101,11 @@ class MAGNUM_GL_EXPORT Buffer: public AbstractObject {
          *      eventually @fn_gl{BindBuffer} and @fn_gl{GetBufferParameter}
          *      with @def_gl{BUFFER_SIZE}, then @fn_gl2_keyword{GetNamedBufferSubData,GetBufferSubData},
          *      eventually @fn_gl_keyword{GetBufferSubData}
-         * @requires_gl Buffer data queries are not available in OpenGL ES and
-         *      WebGL. Use @ref map(), @ref mapRead() or @ref DebugTools::bufferData()
-         *      in OpenGL ES instead.
+         * @requires_gl Buffer data queries are not available in OpenGL ES. Use
+         *      @ref map(), @ref mapRead() or @ref DebugTools::bufferData()
+         *      instead.
+         * @requires_webgl20 Buffer data queries are not available in
+         *      WebGL 1.0. Emscripten 2.0.17 or higher is required in WebGL2.
          */
         Containers::Array<char> data();
 
@@ -1119,9 +1121,11 @@ class MAGNUM_GL_EXPORT Buffer: public AbstractObject {
          * @see @ref size(), @ref data(), @ref setSubData(), @ref setTargetHint(),
          *      @fn_gl2_keyword{GetNamedBufferSubData,GetBufferSubData},
          *      eventually @fn_gl{BindBuffer} and @fn_gl_keyword{GetBufferSubData}
-         * @requires_gl Buffer data queries are not available in OpenGL ES and
-         *      WebGL. Use @ref map(), @ref mapRead() or @ref DebugTools::bufferData()
-         *      in OpenGL ES instead.
+         * @requires_gl Buffer data queries are not available in OpenGL ES. Use
+         *      @ref map(), @ref mapRead() or @ref DebugTools::bufferData() in
+         *      OpenGL ES instead.
+         * @requires_webgl20 Buffer data queries are not available in
+         *      WebGL 1.0. Emscripten 2.0.17 or higher is required in WebGL2.
          */
         Containers::Array<char> subData(GLintptr offset, GLsizeiptr size);
         #endif
@@ -1357,8 +1361,10 @@ class MAGNUM_GL_EXPORT Buffer: public AbstractObject {
         void MAGNUM_GL_LOCAL getParameterImplementationDSA(GLenum value, GLint* data);
         #endif
 
-        #ifndef MAGNUM_TARGET_GLES
+        #if !defined(MAGNUM_TARGET_GLES) || (defined(MAGNUM_TARGET_WEBGL) && !defined(MAGNUM_TARGET_GLES2) && __EMSCRIPTEN_major__*10000 + __EMSCRIPTEN_minor__*100 + __EMSCRIPTEN_tiny__ >= 20017)
         void MAGNUM_GL_LOCAL getSubDataImplementationDefault(GLintptr offset, GLsizeiptr size, GLvoid* data);
+        #endif
+        #ifndef MAGNUM_TARGET_GLES
         void MAGNUM_GL_LOCAL getSubDataImplementationDSA(GLintptr offset, GLsizeiptr size, GLvoid* data);
         #endif
 
diff --git a/src/Magnum/GL/Implementation/BufferState.cpp b/src/Magnum/GL/Implementation/BufferState.cpp
index f71a537693..e1dbb85adc 100644
--- a/src/Magnum/GL/Implementation/BufferState.cpp
+++ b/src/Magnum/GL/Implementation/BufferState.cpp
@@ -126,7 +126,7 @@ BufferState::BufferState(Context& context, Containers::StaticArrayView<Implement
         storageImplementation = &Buffer::storageImplementationDefault;
         #endif
         getParameterImplementation = &Buffer::getParameterImplementationDefault;
-        #ifndef MAGNUM_TARGET_GLES
+        #if !defined(MAGNUM_TARGET_GLES) || (defined(MAGNUM_TARGET_WEBGL) && !defined(MAGNUM_TARGET_GLES2) && __EMSCRIPTEN_major__*10000 + __EMSCRIPTEN_minor__*100 + __EMSCRIPTEN_tiny__ >= 20017)
         getSubDataImplementation = &Buffer::getSubDataImplementationDefault;
         #endif
         dataImplementation = &Buffer::dataImplementationDefault;
diff --git a/src/Magnum/GL/Implementation/BufferState.h b/src/Magnum/GL/Implementation/BufferState.h
index 93b74a08af..32760a70ce 100644
--- a/src/Magnum/GL/Implementation/BufferState.h
+++ b/src/Magnum/GL/Implementation/BufferState.h
@@ -59,7 +59,7 @@ struct BufferState {
     void(Buffer::*storageImplementation)(Containers::ArrayView<const void>, Buffer::StorageFlags);
     #endif
     void(Buffer::*getParameterImplementation)(GLenum, GLint*);
-    #ifndef MAGNUM_TARGET_GLES2
+    #if !defined(MAGNUM_TARGET_GLES) || (defined(MAGNUM_TARGET_WEBGL) && !defined(MAGNUM_TARGET_GLES2) && __EMSCRIPTEN_major__*10000 + __EMSCRIPTEN_minor__*100 + __EMSCRIPTEN_tiny__ >= 20017)
     void(Buffer::*getSubDataImplementation)(GLintptr, GLsizeiptr, GLvoid*);
     #endif
     void(Buffer::*dataImplementation)(GLsizeiptr, const GLvoid*, BufferUsage);
diff --git a/src/Magnum/GL/Test/BufferGLTest.cpp b/src/Magnum/GL/Test/BufferGLTest.cpp
index ef6d42202e..171fa07fb6 100644
--- a/src/Magnum/GL/Test/BufferGLTest.cpp
+++ b/src/Magnum/GL/Test/BufferGLTest.cpp
@@ -34,6 +34,10 @@
 #include "Magnum/GL/Extensions.h"
 #include "Magnum/GL/OpenGLTester.h"
 
+#ifndef MAGNUM_TARGET_GLES2
+#include "Magnum/DebugTools/BufferData.h"
+#endif
+
 #ifndef MAGNUM_TARGET_WEBGL
 #include <Corrade/Containers/String.h>
 #endif
@@ -138,15 +142,14 @@ void BufferGLTest::constructFromData() {
     CORRADE_COMPARE(c.size(), 5*4);
     CORRADE_COMPARE(d.size(), 5*4);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
-    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(a.data()),
+    #ifndef MAGNUM_TARGET_GLES2
+    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(DebugTools::bufferData(a)),
         Containers::arrayView(data),
         TestSuite::Compare::Container);
-    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(b.data()),
+    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(DebugTools::bufferData(b)),
         Containers::arrayView(data),
         TestSuite::Compare::Container);
-    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(c.data()),
+    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(DebugTools::bufferData(c)),
         Containers::arrayView(data),
         TestSuite::Compare::Container);
     /* d's data is undefined, not testing */
@@ -307,10 +310,9 @@ void BufferGLTest::data() {
     MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE(buffer.size(), 5*4);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
     MAGNUM_VERIFY_NO_GL_ERROR();
-    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(buffer.data()),
+    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(DebugTools::bufferData(buffer)),
         Containers::arrayView(data),
         TestSuite::Compare::Container);
     #endif
@@ -320,10 +322,9 @@ void BufferGLTest::data() {
     MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE(buffer.size(), 5*4);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
     MAGNUM_VERIFY_NO_GL_ERROR();
-    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(buffer.data()),
+    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(DebugTools::bufferData(buffer)),
         Containers::arrayView(data),
         TestSuite::Compare::Container);
     #endif
@@ -334,10 +335,9 @@ void BufferGLTest::data() {
     MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE(buffer.size(), 5*4);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
     MAGNUM_VERIFY_NO_GL_ERROR();
-    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(buffer.subData(4, 3*4)),
+    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(DebugTools::bufferSubData(buffer, 4, 3*4)),
         Containers::arrayView(subData),
         TestSuite::Compare::Container);
     #endif
@@ -347,10 +347,9 @@ void BufferGLTest::data() {
     MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE(buffer.size(), 5*4);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
     MAGNUM_VERIFY_NO_GL_ERROR();
-    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(buffer.subData(4, 3*4)),
+    CORRADE_COMPARE_AS(Containers::arrayCast<Int>(DebugTools::bufferSubData(buffer, 4, 3*4)),
         Containers::arrayView(subData),
         TestSuite::Compare::Container);
     #endif
@@ -385,9 +384,8 @@ void BufferGLTest::map() {
     CORRADE_VERIFY(buffer.unmap());
     MAGNUM_VERIFY_NO_GL_ERROR();
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
-    Containers::Array<char> changedContents = buffer.data();
+    #ifndef MAGNUM_TARGET_GLES2
+    Containers::Array<char> changedContents = DebugTools::bufferData(buffer);
     CORRADE_COMPARE(changedContents.size(), 5);
     CORRADE_COMPARE(changedContents[3], 107);
     #endif
@@ -417,9 +415,8 @@ void BufferGLTest::mapRange() {
     CORRADE_VERIFY(buffer.unmap());
     MAGNUM_VERIFY_NO_GL_ERROR();
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
-    Containers::Array<char> changedContents = buffer.data();
+    #ifndef MAGNUM_TARGET_GLES2
+    Containers::Array<char> changedContents = DebugTools::bufferData(buffer);
     CORRADE_COMPARE(changedContents.size(), 5);
     CORRADE_COMPARE(changedContents[4], 107);
     #endif
@@ -457,9 +454,8 @@ void BufferGLTest::mapRangeExplicitFlush() {
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     /* Flushed range should be changed */
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
-    Containers::Array<char> changedContents = buffer.data();
+    #ifndef MAGNUM_TARGET_GLES2
+    Containers::Array<char> changedContents = DebugTools::bufferData(buffer);
     CORRADE_COMPARE(changedContents.size(), 5);
     CORRADE_COMPARE(changedContents[4], 107);
     #endif
@@ -478,9 +474,8 @@ void BufferGLTest::copy() {
     Buffer::copy(buffer1, buffer2, 1, 2, 3);
     MAGNUM_VERIFY_NO_GL_ERROR();
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
-    const Containers::Array<char> subContents = buffer2.subData(2, 3);
+    #ifndef MAGNUM_TARGET_GLES2
+    const Containers::Array<char> subContents = DebugTools::bufferSubData(buffer2, 2, 3);
     CORRADE_COMPARE_AS(subContents, Containers::arrayView(data).slice(1, 4),
         TestSuite::Compare::Container);
     #endif
diff --git a/src/Magnum/GL/Test/BufferImageGLTest.cpp b/src/Magnum/GL/Test/BufferImageGLTest.cpp
index 915f485872..74691ce70a 100644
--- a/src/Magnum/GL/Test/BufferImageGLTest.cpp
+++ b/src/Magnum/GL/Test/BufferImageGLTest.cpp
@@ -33,6 +33,10 @@
 #include "Magnum/GL/PixelFormat.h"
 #include "Magnum/GL/OpenGLTester.h"
 
+#ifndef MAGNUM_TARGET_GLES2
+#include "Magnum/DebugTools/BufferData.h"
+#endif
+
 namespace Magnum { namespace GL { namespace Test { namespace {
 
 struct BufferImageGLTest: OpenGLTester {
@@ -98,10 +102,6 @@ void BufferImageGLTest::construct() {
     BufferImage2D a{PixelStorage{}.setAlignment(1),
         PixelFormat::Red, PixelType::UnsignedByte, {1, 3}, data, BufferUsage::StaticDraw};
 
-    #ifndef MAGNUM_TARGET_GLES
-    const auto imageData = a.buffer().data();
-    #endif
-
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     CORRADE_COMPARE(a.storage().alignment(), 1);
@@ -110,8 +110,9 @@ void BufferImageGLTest::construct() {
     CORRADE_COMPARE(a.size(), Vector2i(1, 3));
     CORRADE_COMPARE(a.dataSize(), 3);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
+    const auto imageData = DebugTools::bufferData(a.buffer());
+    MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE_AS(imageData, Containers::arrayView(data),
         TestSuite::Compare::Container);
     #endif
@@ -122,10 +123,6 @@ void BufferImageGLTest::constructGeneric() {
     BufferImage2D a{PixelStorage{}.setAlignment(1),
         Magnum::PixelFormat::R8Unorm, {1, 3}, data, BufferUsage::StaticDraw};
 
-    #ifndef MAGNUM_TARGET_GLES
-    const auto imageData = a.buffer().data();
-    #endif
-
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     CORRADE_COMPARE(a.storage().alignment(), 1);
@@ -134,8 +131,9 @@ void BufferImageGLTest::constructGeneric() {
     CORRADE_COMPARE(a.size(), Vector2i(1, 3));
     CORRADE_COMPARE(a.dataSize(), 3);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
+    const auto imageData = DebugTools::bufferData(a.buffer());
+    MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE_AS(imageData, Containers::arrayView(data),
         TestSuite::Compare::Container);
     #endif
@@ -150,10 +148,6 @@ void BufferImageGLTest::constructCompressed() {
         CompressedPixelFormat::RGBAS3tcDxt1,
         {4, 4}, data, BufferUsage::StaticDraw};
 
-    #ifndef MAGNUM_TARGET_GLES
-    const auto imageData = a.buffer().data();
-    #endif
-
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     #ifndef MAGNUM_TARGET_GLES
@@ -163,8 +157,9 @@ void BufferImageGLTest::constructCompressed() {
     CORRADE_COMPARE(a.size(), Vector2i(4, 4));
     CORRADE_COMPARE(a.dataSize(), 8);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
+    const auto imageData = DebugTools::bufferData(a.buffer());
+    MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE_AS(imageData, Containers::arrayView(data),
         TestSuite::Compare::Container);
     #endif
@@ -179,10 +174,6 @@ void BufferImageGLTest::constructCompressedGeneric() {
         Magnum::CompressedPixelFormat::Bc1RGBAUnorm,
         {4, 4}, data, BufferUsage::StaticDraw};
 
-    #ifndef MAGNUM_TARGET_GLES
-    const auto imageData = a.buffer().data();
-    #endif
-
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     #ifndef MAGNUM_TARGET_GLES
@@ -192,8 +183,9 @@ void BufferImageGLTest::constructCompressedGeneric() {
     CORRADE_COMPARE(a.size(), Vector2i(4, 4));
     CORRADE_COMPARE(a.dataSize(), 8);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
+    const auto imageData = DebugTools::bufferData(a.buffer());
+    MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE_AS(imageData, Containers::arrayView(data),
         TestSuite::Compare::Container);
     #endif
@@ -208,10 +200,6 @@ void BufferImageGLTest::constructBuffer() {
     BufferImage2D a{PixelStorage{}.setAlignment(1),
         PixelFormat::Red, PixelType::UnsignedByte, {1, 3}, std::move(buffer), sizeof(data)};
 
-    #ifndef MAGNUM_TARGET_GLES
-    const auto imageData = a.buffer().data();
-    #endif
-
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     CORRADE_VERIFY(!buffer.id());
@@ -222,8 +210,9 @@ void BufferImageGLTest::constructBuffer() {
     CORRADE_COMPARE(a.size(), Vector2i(1, 3));
     CORRADE_COMPARE(a.dataSize(), 3);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
+    const auto imageData = DebugTools::bufferData(a.buffer());
+    MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE_AS(imageData, Containers::arrayView(data),
         TestSuite::Compare::Container);
     #endif
@@ -238,10 +227,6 @@ void BufferImageGLTest::constructBufferGeneric() {
     BufferImage2D a{PixelStorage{}.setAlignment(1),
         Magnum::PixelFormat::R8Unorm, {1, 3}, std::move(buffer), sizeof(data)};
 
-    #ifndef MAGNUM_TARGET_GLES
-    const auto imageData = a.buffer().data();
-    #endif
-
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     CORRADE_VERIFY(!buffer.id());
@@ -252,8 +237,9 @@ void BufferImageGLTest::constructBufferGeneric() {
     CORRADE_COMPARE(a.size(), Vector2i(1, 3));
     CORRADE_COMPARE(a.dataSize(), 3);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
+    const auto imageData = DebugTools::bufferData(a.buffer());
+    MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE_AS(imageData, Containers::arrayView(data),
         TestSuite::Compare::Container);
     #endif
@@ -272,10 +258,6 @@ void BufferImageGLTest::constructBufferCompressed() {
         CompressedPixelFormat::RGBAS3tcDxt1,
         {4, 4}, std::move(buffer), sizeof(data)};
 
-    #ifndef MAGNUM_TARGET_GLES
-    const auto imageData = a.buffer().data();
-    #endif
-
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     #ifndef MAGNUM_TARGET_GLES
@@ -287,8 +269,9 @@ void BufferImageGLTest::constructBufferCompressed() {
     CORRADE_COMPARE(a.size(), Vector2i(4, 4));
     CORRADE_COMPARE(a.dataSize(), 8);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
+    const auto imageData = DebugTools::bufferData(a.buffer());
+    MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE_AS(imageData, Containers::arrayView(data),
         TestSuite::Compare::Container);
     #endif
@@ -307,10 +290,6 @@ void BufferImageGLTest::constructBufferCompressedGeneric() {
         Magnum::CompressedPixelFormat::Bc1RGBAUnorm,
         {4, 4}, std::move(buffer), sizeof(data)};
 
-    #ifndef MAGNUM_TARGET_GLES
-    const auto imageData = a.buffer().data();
-    #endif
-
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     #ifndef MAGNUM_TARGET_GLES
@@ -322,8 +301,9 @@ void BufferImageGLTest::constructBufferCompressedGeneric() {
     CORRADE_COMPARE(a.size(), Vector2i(4, 4));
     CORRADE_COMPARE(a.dataSize(), 8);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
+    const auto imageData = DebugTools::bufferData(a.buffer());
+    MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE_AS(imageData, Containers::arrayView(data),
         TestSuite::Compare::Container);
     #endif
@@ -487,10 +467,6 @@ void BufferImageGLTest::setData() {
     const UnsignedShort data2[2*4] = { 1, 2, 3, 4, 5, 6, 7, 8 };
     a.setData(PixelFormat::RGBA, PixelType::UnsignedShort, {1, 2}, data2, BufferUsage::StaticDraw);
 
-    #ifndef MAGNUM_TARGET_GLES
-    const auto imageData = a.buffer().data();
-    #endif
-
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     CORRADE_COMPARE(a.storage().alignment(), 4);
@@ -499,8 +475,9 @@ void BufferImageGLTest::setData() {
     CORRADE_COMPARE(a.size(), Vector2i(1, 2));
     CORRADE_COMPARE(a.dataSize(), 16);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
+    const auto imageData = DebugTools::bufferData(a.buffer());
+    MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE_AS(Containers::arrayCast<UnsignedShort>(imageData),
         Containers::arrayView(data2),
         TestSuite::Compare::Container);
@@ -515,10 +492,6 @@ void BufferImageGLTest::setDataGeneric() {
     const UnsignedShort data2[2*4] = { 1, 2, 3, 4, 5, 6, 7, 8 };
     a.setData(Magnum::PixelFormat::RGBA16Unorm, {1, 2}, data2, BufferUsage::StaticDraw);
 
-    #ifndef MAGNUM_TARGET_GLES
-    const auto imageData = a.buffer().data();
-    #endif
-
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     CORRADE_COMPARE(a.storage().alignment(), 4);
@@ -527,8 +500,9 @@ void BufferImageGLTest::setDataGeneric() {
     CORRADE_COMPARE(a.size(), Vector2i(1, 2));
     CORRADE_COMPARE(a.dataSize(), 16);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
+    const auto imageData = DebugTools::bufferData(a.buffer());
+    MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE_AS(Containers::arrayCast<UnsignedShort>(imageData),
         Containers::arrayView(data2),
         TestSuite::Compare::Container);
@@ -546,10 +520,6 @@ void BufferImageGLTest::setDataCompressed() {
         #endif
         CompressedPixelFormat::RGBAS3tcDxt3, {8, 4}, data2, BufferUsage::StaticDraw);
 
-    #ifndef MAGNUM_TARGET_GLES
-    const auto imageData = a.buffer().data();
-    #endif
-
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     #ifndef MAGNUM_TARGET_GLES
@@ -559,8 +529,9 @@ void BufferImageGLTest::setDataCompressed() {
     CORRADE_COMPARE(a.size(), Vector2i(8, 4));
     CORRADE_COMPARE(a.dataSize(), 16);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
+    const auto imageData = DebugTools::bufferData(a.buffer());
+    MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE_AS(imageData, Containers::arrayView(data2),
         TestSuite::Compare::Container);
     #endif
@@ -577,10 +548,6 @@ void BufferImageGLTest::setDataCompressedGeneric() {
         #endif
         Magnum::CompressedPixelFormat::Bc2RGBAUnorm, {8, 4}, data2, BufferUsage::StaticDraw);
 
-    #ifndef MAGNUM_TARGET_GLES
-    const auto imageData = a.buffer().data();
-    #endif
-
     MAGNUM_VERIFY_NO_GL_ERROR();
 
     #ifndef MAGNUM_TARGET_GLES
@@ -590,8 +557,9 @@ void BufferImageGLTest::setDataCompressedGeneric() {
     CORRADE_COMPARE(a.size(), Vector2i(8, 4));
     CORRADE_COMPARE(a.dataSize(), 16);
 
-    /** @todo How to verify the contents in ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
+    const auto imageData = DebugTools::bufferData(a.buffer());
+    MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE_AS(imageData, Containers::arrayView(data2),
         TestSuite::Compare::Container);
     #endif
diff --git a/src/Magnum/GL/Test/CMakeLists.txt b/src/Magnum/GL/Test/CMakeLists.txt
index 5f9a38711e..651848fb5d 100644
--- a/src/Magnum/GL/Test/CMakeLists.txt
+++ b/src/Magnum/GL/Test/CMakeLists.txt
@@ -75,9 +75,7 @@ if(BUILD_GL_TESTS)
     find_package(Corrade REQUIRED PluginManager)
 
     corrade_add_test(GLAbstractTextureGLTest AbstractTextureGLTest.cpp LIBRARIES MagnumOpenGLTesterTestLib)
-    corrade_add_test(GLBufferGLTest BufferGLTest.cpp LIBRARIES MagnumOpenGLTester)
     corrade_add_test(GLCubeMapTextureGLTest CubeMapTextureGLTest.cpp LIBRARIES MagnumOpenGLTesterTestLib)
-    corrade_add_test(GLFramebufferGLTest FramebufferGLTest.cpp LIBRARIES MagnumOpenGLTesterTestLib)
     corrade_add_test(GLMeshGLTest MeshGLTest.cpp LIBRARIES MagnumOpenGLTesterTestLib)
     corrade_add_test(GLRenderbufferGLTest RenderbufferGLTest.cpp LIBRARIES MagnumOpenGLTester)
     corrade_add_test(GLTextureGLTest TextureGLTest.cpp LIBRARIES MagnumOpenGLTesterTestLib)
@@ -89,6 +87,16 @@ if(BUILD_GL_TESTS)
         ${GLAbstractShaderProgramGLTest_RES}
         LIBRARIES MagnumOpenGLTester)
 
+    corrade_add_test(GLBufferGLTest BufferGLTest.cpp LIBRARIES MagnumOpenGLTester)
+    if(NOT MAGNUM_TARGET_GLES2)
+        target_link_libraries(GLBufferGLTest PRIVATE MagnumDebugTools)
+    endif()
+
+    corrade_add_test(GLFramebufferGLTest FramebufferGLTest.cpp LIBRARIES MagnumOpenGLTesterTestLib)
+    if(NOT MAGNUM_TARGET_GLES2)
+        target_link_libraries(GLFramebufferGLTest PRIVATE MagnumDebugTools)
+    endif()
+
     corrade_add_test(GLContextGLTest ContextGLTest.cpp LIBRARIES MagnumOpenGLTester)
     if(NOT CORRADE_TARGET_EMSCRIPTEN)
         set(THREADS_PREFER_PTHREAD_FLAG TRUE)
@@ -162,10 +170,10 @@ if(BUILD_GL_TESTS)
     endif()
 
     if(NOT MAGNUM_TARGET_GLES2)
-        corrade_add_test(GLBufferImageGLTest BufferImageGLTest.cpp LIBRARIES MagnumOpenGLTesterTestLib)
+        corrade_add_test(GLBufferImageGLTest BufferImageGLTest.cpp LIBRARIES MagnumOpenGLTesterTestLib MagnumDebugTools)
         corrade_add_test(GLPrimitiveQueryGLTest PrimitiveQueryGLTest.cpp LIBRARIES MagnumOpenGLTester)
         corrade_add_test(GLTextureArrayGLTest TextureArrayGLTest.cpp LIBRARIES MagnumOpenGLTester)
-        corrade_add_test(GLTransformFeedbackGLTest TransformFeedbackGLTest.cpp LIBRARIES MagnumOpenGLTester)
+        corrade_add_test(GLTransformFeedbackGLTest TransformFeedbackGLTest.cpp LIBRARIES MagnumOpenGLTester MagnumDebugTools)
     endif()
 
     if(NOT MAGNUM_TARGET_GLES2 AND NOT MAGNUM_TARGET_WEBGL)
diff --git a/src/Magnum/GL/Test/FramebufferGLTest.cpp b/src/Magnum/GL/Test/FramebufferGLTest.cpp
index e9d1724c3d..798fb4b423 100644
--- a/src/Magnum/GL/Test/FramebufferGLTest.cpp
+++ b/src/Magnum/GL/Test/FramebufferGLTest.cpp
@@ -57,6 +57,10 @@
 #include "Magnum/GL/RectangleTexture.h"
 #endif
 
+#ifndef MAGNUM_TARGET_GLES2
+#include "Magnum/DebugTools/BufferData.h"
+#endif
+
 namespace Magnum { namespace GL { namespace Test { namespace {
 
 struct FramebufferGLTest: OpenGLTester {
@@ -1701,9 +1705,9 @@ void FramebufferGLTest::readBuffer() {
     CORRADE_COMPARE(colorImage.size(), Vector2i(8, 16));
 
     MAGNUM_VERIFY_NO_GL_ERROR();
-    /** @todo How to test this on ES? */
-    #ifndef MAGNUM_TARGET_GLES
-    auto colorData = colorImage.buffer().data();
+
+    #ifndef MAGNUM_TARGET_GLES2
+    auto colorData = DebugTools::bufferData(colorImage.buffer());
     CORRADE_COMPARE(colorData.size(), (DataOffset + 8*16)*sizeof(Color4ub));
     CORRADE_COMPARE(Containers::arrayCast<Color4ub>(colorData)[DataOffset], Color4ub(128, 64, 32, 17));
     #endif
diff --git a/src/Magnum/GL/Test/TransformFeedbackGLTest.cpp b/src/Magnum/GL/Test/TransformFeedbackGLTest.cpp
index 25a3b008f9..ec2863e538 100644
--- a/src/Magnum/GL/Test/TransformFeedbackGLTest.cpp
+++ b/src/Magnum/GL/Test/TransformFeedbackGLTest.cpp
@@ -24,8 +24,11 @@
 */
 
 #include <tuple>
+#include <Corrade/Containers/Array.h>
 #include <Corrade/Containers/Reference.h>
+#include <Corrade/TestSuite/Compare/Container.h>
 
+#include "Magnum/DebugTools/BufferData.h"
 #include "Magnum/Image.h"
 #include "Magnum/GL/AbstractShaderProgram.h"
 #include "Magnum/GL/Buffer.h"
@@ -307,14 +310,11 @@ void TransformFeedbackGLTest::attachBase() {
 
     MAGNUM_VERIFY_NO_GL_ERROR();
 
-    #ifdef MAGNUM_TARGET_WEBGL
-    CORRADE_SKIP("Can't map buffers on WebGL.");
-    #else
-    auto data = Containers::arrayCast<const Vector2>(output.mapRead(0, 2*sizeof(Vector2)));
-    CORRADE_COMPARE(data[0], Vector2(1.0f, -1.0f));
-    CORRADE_COMPARE(data[1], Vector2(0.0f, 0.0f));
-    output.unmap();
-    #endif
+    auto data = DebugTools::bufferData(output);
+    MAGNUM_VERIFY_NO_GL_ERROR();
+    CORRADE_COMPARE_AS(Containers::arrayCast<Vector2>(data),
+        Containers::arrayView<Vector2>({{1.0f, -1.0f}, {0.0f, 0.0f}}),
+        TestSuite::Compare::Container);
 }
 
 void TransformFeedbackGLTest::attachRange() {
@@ -354,14 +354,11 @@ void TransformFeedbackGLTest::attachRange() {
 
     MAGNUM_VERIFY_NO_GL_ERROR();
 
-    #ifdef MAGNUM_TARGET_WEBGL
-    CORRADE_SKIP("Can't map buffers on WebGL.");
-    #else
-    auto data = Containers::arrayCast<const Vector2>(output.mapRead(256, 2*sizeof(Vector2)));
-    CORRADE_COMPARE(data[0], Vector2(1.0f, -1.0f));
-    CORRADE_COMPARE(data[1], Vector2(0.0f, 0.0f));
-    output.unmap();
-    #endif
+    auto data = DebugTools::bufferSubData(output, 256, 2*sizeof(Vector2));
+    MAGNUM_VERIFY_NO_GL_ERROR();
+    CORRADE_COMPARE_AS(Containers::arrayCast<Vector2>(data),
+        Containers::arrayView<Vector2>({{1.0f, -1.0f}, {0.0f, 0.0f}}),
+        TestSuite::Compare::Container);
 }
 
 struct XfbMultiShader: AbstractShaderProgram {
@@ -445,19 +442,17 @@ void TransformFeedbackGLTest::attachBases() {
 
     MAGNUM_VERIFY_NO_GL_ERROR();
 
-    #ifdef MAGNUM_TARGET_WEBGL
-    CORRADE_SKIP("Can't map buffers on WebGL.");
-    #else
-    auto data1 = Containers::arrayCast<const Vector2>(output1.mapRead(0, 2*sizeof(Vector2)));
-    CORRADE_COMPARE(data1[0], Vector2(1.0f, -1.0f));
-    CORRADE_COMPARE(data1[1], Vector2(0.0f, 0.0f));
-    output1.unmap();
-
-    auto data2 = Containers::arrayCast<const Float>(output2.mapRead(0, 2*sizeof(Float)));
-    CORRADE_COMPARE(data2[0], 0.0f);
-    CORRADE_COMPARE(data2[1], -2.0f);
-    output2.unmap();
-    #endif
+    auto data1 = DebugTools::bufferData(output1);
+    MAGNUM_VERIFY_NO_GL_ERROR();
+    CORRADE_COMPARE_AS(Containers::arrayCast<Vector2>(data1),
+        Containers::arrayView<Vector2>({{1.0f, -1.0f}, {0.0f, 0.0f}}),
+        TestSuite::Compare::Container);
+
+    auto data2 = DebugTools::bufferData(output2);
+    MAGNUM_VERIFY_NO_GL_ERROR();
+    CORRADE_COMPARE_AS(Containers::arrayCast<Float>(data2),
+        Containers::arrayView({0.0f, -2.0f}),
+        TestSuite::Compare::Container);
 }
 
 void TransformFeedbackGLTest::attachRanges() {
@@ -502,19 +497,17 @@ void TransformFeedbackGLTest::attachRanges() {
 
     MAGNUM_VERIFY_NO_GL_ERROR();
 
-    #ifdef MAGNUM_TARGET_WEBGL
-    CORRADE_SKIP("Can't map buffers on WebGL.");
-    #else
-    auto data1 = Containers::arrayCast<const Vector2>(output1.mapRead(256, 2*sizeof(Vector2)));
-    CORRADE_COMPARE(data1[0], Vector2(1.0f, -1.0f));
-    CORRADE_COMPARE(data1[1], Vector2(0.0f, 0.0f));
-    output1.unmap();
-
-    auto data2 = Containers::arrayCast<const Float>(output2.mapRead(512, 2*sizeof(Float)));
-    CORRADE_COMPARE(data2[0], 0.0f);
-    CORRADE_COMPARE(data2[1], -2.0f);
-    output2.unmap();
-    #endif
+    auto data1 = DebugTools::bufferSubData(output1, 256, 2*sizeof(Vector2));
+    MAGNUM_VERIFY_NO_GL_ERROR();
+    CORRADE_COMPARE_AS(Containers::arrayCast<Vector2>(data1),
+        Containers::arrayView<Vector2>({{1.0f, -1.0f}, {0.0f, 0.0f}}),
+        TestSuite::Compare::Container);
+
+    auto data2 = DebugTools::bufferSubData(output2, 512, 2*sizeof(Float));
+    MAGNUM_VERIFY_NO_GL_ERROR();
+    CORRADE_COMPARE_AS(Containers::arrayCast<Float>(data2),
+        Containers::arrayView({0.0f, -2.0f}),
+        TestSuite::Compare::Container);
 }
 
 #ifndef MAGNUM_TARGET_GLES
diff --git a/src/Magnum/Text/Test/CMakeLists.txt b/src/Magnum/Text/Test/CMakeLists.txt
index 9aac7e3312..cdf641aa87 100644
--- a/src/Magnum/Text/Test/CMakeLists.txt
+++ b/src/Magnum/Text/Test/CMakeLists.txt
@@ -53,4 +53,7 @@ if(TARGET_GL AND BUILD_GL_TESTS)
     corrade_add_test(TextDistanceFieldGlyphCacheGLTest DistanceFieldGlyphCacheGLTest.cpp LIBRARIES MagnumText MagnumOpenGLTester)
     corrade_add_test(TextGlyphCacheGLTest GlyphCacheGLTest.cpp LIBRARIES MagnumText MagnumOpenGLTester)
     corrade_add_test(TextRendererGLTest RendererGLTest.cpp LIBRARIES MagnumText MagnumOpenGLTester)
+    if(NOT MAGNUM_TARGET_GLES2)
+        target_link_libraries(TextRendererGLTest PRIVATE MagnumDebugTools)
+    endif()
 endif()
diff --git a/src/Magnum/Text/Test/RendererGLTest.cpp b/src/Magnum/Text/Test/RendererGLTest.cpp
index 276f3fbc25..1907d8fcde 100644
--- a/src/Magnum/Text/Test/RendererGLTest.cpp
+++ b/src/Magnum/Text/Test/RendererGLTest.cpp
@@ -32,6 +32,10 @@
 #include "Magnum/Text/AbstractFont.h"
 #include "Magnum/Text/Renderer.h"
 
+#ifndef MAGNUM_TARGET_GLES2
+#include "Magnum/DebugTools/BufferData.h"
+#endif
+
 namespace Magnum { namespace Text { namespace Test { namespace {
 
 struct RendererGLTest: GL::OpenGLTester {
@@ -187,10 +191,9 @@ void RendererGLTest::renderMesh() {
     /* Bounds */
     CORRADE_COMPARE(bounds, Range2D({0.0f, -0.5f}, {5.0f, 1.0f}).translated(offset));
 
-    /** @todo How to verify this on ES? */
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
     /* Vertex buffer contents */
-    Containers::Array<char> vertices = vertexBuffer.data();
+    Containers::Array<char> vertices = DebugTools::bufferData(vertexBuffer);
     CORRADE_COMPARE_AS(Containers::arrayCast<const Float>(vertices),
         Containers::arrayView<Float>({
             0.0f + offset.x(),  0.5f + offset.y(), 0.0f, 10.0f,
@@ -208,8 +211,8 @@ void RendererGLTest::renderMesh() {
             5.0f + offset.x(),   1.0f + offset.y(), 18.0f, 10.0f,
             5.0f + offset.x(),  -0.5f + offset.y(), 18.0f,  0.0f
         }), TestSuite::Compare::Container);
-
-    Containers::Array<char> indices = indexBuffer.data();
+    /* Index buffer contents */
+    Containers::Array<char> indices = DebugTools::bufferData(indexBuffer);
     CORRADE_COMPARE_AS(Containers::arrayCast<const UnsignedByte>(indices),
         Containers::arrayView<UnsignedByte>({
             0,  1,  2,  1,  3,  2,
@@ -220,10 +223,11 @@ void RendererGLTest::renderMesh() {
 }
 
 void RendererGLTest::renderMeshIndexType() {
-    #ifndef MAGNUM_TARGET_GLES
+    #ifndef MAGNUM_TARGET_GLES2
     TestFont font;
     GL::Mesh mesh{NoCreate};
-    GL::Buffer vertexBuffer, indexBuffer;
+    GL::Buffer vertexBuffer{GL::Buffer::TargetHint::Array};
+    GL::Buffer indexBuffer{GL::Buffer::TargetHint::ElementArray};
 
     /* Sizes: four vertices per glyph, each vertex has 2D position and 2D
        texture coordinates, each float is four bytes; six indices per glyph. */
@@ -232,7 +236,7 @@ void RendererGLTest::renderMeshIndexType() {
     std::tie(mesh, std::ignore) = Text::Renderer3D::render(font, nullGlyphCache,
         1.0f, std::string(64, 'a'), vertexBuffer, indexBuffer, GL::BufferUsage::StaticDraw);
     MAGNUM_VERIFY_NO_GL_ERROR();
-    Containers::Array<char> indicesByte = indexBuffer.data();
+    Containers::Array<char> indicesByte = DebugTools::bufferData(indexBuffer);
     CORRADE_COMPARE(vertexBuffer.size(), 256*(2 + 2)*4);
     CORRADE_COMPARE(indicesByte.size(), 64*6);
     CORRADE_COMPARE_AS(Containers::arrayCast<const UnsignedByte>(indicesByte).prefix(18),
@@ -246,7 +250,7 @@ void RendererGLTest::renderMeshIndexType() {
     std::tie(mesh, std::ignore) = Text::Renderer3D::render(font, nullGlyphCache,
         1.0f, std::string(65, 'a'), vertexBuffer, indexBuffer, GL::BufferUsage::StaticDraw);
     MAGNUM_VERIFY_NO_GL_ERROR();
-    Containers::Array<char> indicesShort = indexBuffer.data();
+    Containers::Array<char> indicesShort = DebugTools::bufferData(indexBuffer);
     CORRADE_COMPARE(vertexBuffer.size(), 260*(2 + 2)*4);
     CORRADE_COMPARE(indicesShort.size(), 65*6*2);
     CORRADE_COMPARE_AS(Containers::arrayCast<const UnsignedShort>(indicesShort).prefix(18),
@@ -256,7 +260,7 @@ void RendererGLTest::renderMeshIndexType() {
             8,  9, 10,  9, 11, 10
         }), TestSuite::Compare::Container);
     #else
-    CORRADE_SKIP("Can't verify buffer contents on OpenGL ES.");
+    CORRADE_SKIP("Can't verify buffer contents on OpenGL ES 2.0.");
     #endif
 }
 
@@ -280,9 +284,9 @@ void RendererGLTest::mutableText() {
     renderer.reserve(4, GL::BufferUsage::DynamicDraw, GL::BufferUsage::DynamicDraw);
     MAGNUM_VERIFY_NO_GL_ERROR();
     CORRADE_COMPARE(renderer.capacity(), 4);
-    /** @todo How to verify this on ES? */
-    #ifndef MAGNUM_TARGET_GLES
-    Containers::Array<char> indices = renderer.indexBuffer().data();
+
+    #ifndef MAGNUM_TARGET_GLES2
+    Containers::Array<char> indices = DebugTools::bufferData(renderer.indexBuffer());
     CORRADE_COMPARE_AS(Containers::arrayCast<const UnsignedByte>(indices).prefix(24),
         Containers::arrayView<UnsignedByte>({
              0,  1,  2,  1,  3,  2,
@@ -301,9 +305,8 @@ void RendererGLTest::mutableText() {
 
     /* Aligned to line/left, no offset needed */
 
-    /** @todo How to verify this on ES? */
-    #ifndef MAGNUM_TARGET_GLES
-    Containers::Array<char> vertices = renderer.vertexBuffer().data();
+    #ifndef MAGNUM_TARGET_GLES2
+    Containers::Array<char> vertices = DebugTools::bufferData(renderer.vertexBuffer());
     CORRADE_COMPARE_AS(Containers::arrayCast<const Float>(vertices).prefix(48),
         Containers::arrayView<Float>({
             0.0f,  0.5f, 0.0f, 10.0f,