diff --git a/internal/graphicscommand/command.go b/internal/graphicscommand/command.go
index fd0ba3db3..ba6d36433 100644
--- a/internal/graphicscommand/command.go
+++ b/internal/graphicscommand/command.go
@@ -237,11 +237,6 @@ func (c *drawImageCommand) Exec(indexOffsetInBytes int) error {
 		return err
 	}
 	driver().DrawElements(c.nindices, indexOffsetInBytes)
-
-	// glFlush() might be necessary at least on MacBook Pro (a smilar problem at #419),
-	// but basically this pass the tests (esp. TestImageTooManyFill).
-	// As glFlush() causes performance problems, this should be avoided as much as possible.
-	// Let's wait and see, and file a new issue when this problem is newly found.
 	return nil
 }
 
@@ -298,10 +293,7 @@ func (c *replacePixelsCommand) String() string {
 
 // Exec executes the replacePixelsCommand.
 func (c *replacePixelsCommand) Exec(indexOffsetInBytes int) error {
-	// glFlush is necessary on Android.
-	// glTexSubImage2D didn't work without this hack at least on Nexus 5x and NuAns NEO [Reloaded] (#211).
-	driver().Flush()
-	c.dst.image.TexSubImage2D(c.pixels, c.x, c.y, c.width, c.height)
+	c.dst.image.ReplacePixels(c.pixels, c.x, c.y, c.width, c.height)
 	return nil
 }
 
diff --git a/internal/graphicsdriver/graphicsdriver.go b/internal/graphicsdriver/graphicsdriver.go
index fda385672..352ff986b 100644
--- a/internal/graphicsdriver/graphicsdriver.go
+++ b/internal/graphicsdriver/graphicsdriver.go
@@ -36,5 +36,5 @@ type Image interface {
 	Pixels() ([]byte, error)
 	SetAsDestination()
 	SetAsSource()
-	TexSubImage2D(p []byte, x, y, width, height int)
+	ReplacePixels(pixels []byte, x, y, width, height int)
 }
diff --git a/internal/graphicsdriver/opengl/driver.go b/internal/graphicsdriver/opengl/driver.go
index 6099b6ab1..39c76aa7f 100644
--- a/internal/graphicsdriver/opengl/driver.go
+++ b/internal/graphicsdriver/opengl/driver.go
@@ -77,6 +77,10 @@ func (d *Driver) UseProgram(mode graphics.CompositeMode, colorM *affine.ColorM,
 
 func (d *Driver) DrawElements(len int, offsetInBytes int) {
 	theContext.drawElements(len, offsetInBytes)
+	// glFlush() might be necessary at least on MacBook Pro (a smilar problem at #419),
+	// but basically this pass the tests (esp. TestImageTooManyFill).
+	// As glFlush() causes performance problems, this should be avoided as much as possible.
+	// Let's wait and see, and file a new issue when this problem is newly found.
 }
 
 func (d *Driver) Flush() {
diff --git a/internal/graphicsdriver/opengl/image.go b/internal/graphicsdriver/opengl/image.go
index 22f67c019..5f22223f2 100644
--- a/internal/graphicsdriver/opengl/image.go
+++ b/internal/graphicsdriver/opengl/image.go
@@ -100,7 +100,10 @@ func (i *Image) ensureFramebuffer() error {
 	return nil
 }
 
-func (i *Image) TexSubImage2D(p []byte, x, y, width, height int) {
+func (i *Image) ReplacePixels(p []byte, x, y, width, height int) {
+	// glFlush is necessary on Android.
+	// glTexSubImage2D didn't work without this hack at least on Nexus 5x and NuAns NEO [Reloaded] (#211).
+	theContext.flush()
 	theContext.texSubImage2D(i.textureNative, p, x, y, width, height)
 }