--- a/content/canvas/src/WebGLContextGL.cpp
+++ b/content/canvas/src/WebGLContextGL.cpp
@@ -616,16 +616,20 @@ WebGLContext::CopyTexImage2D(WebGLenum t
         if (!(is_pot_assuming_nonnegative(width) &&
               is_pot_assuming_nonnegative(height)))
             return ErrorInvalidValue("copyTexImage2D: with level > 0, width and height must be powers of two");
     }
 
     if (!CanvasUtils::CheckSaneSubrectSize(x,y,width, height, mWidth, mHeight))
         return ErrorInvalidOperation("CopyTexImage2D: copied rectangle out of bounds");
 
+
+    if (mBoundFramebuffer && !mBoundFramebuffer->CheckAndInitializeRenderbuffers())
+        return NS_OK;
+
     WebGLTexture *tex = activeBoundTextureForTarget(target);
     if (!tex)
         return ErrorInvalidOperation("copyTexImage2D: no texture bound to this target");
 
     tex->SetImageInfo(target, level, width, height);
 
     MakeContextCurrent();
 
@@ -655,16 +659,19 @@ WebGLContext::CopyTexSubImage2D(WebGLenu
             break;
         default:
             return ErrorInvalidEnumInfo("CopyTexSubImage2D: target", target);
     }
 
     if (!CanvasUtils::CheckSaneSubrectSize(x,y,width, height, mWidth, mHeight))
         return ErrorInvalidOperation("CopyTexSubImage2D: copied rectangle out of bounds");
 
+    if (mBoundFramebuffer && !mBoundFramebuffer->CheckAndInitializeRenderbuffers())
+        return NS_OK;
+
     MakeContextCurrent();
 
     gl->fCopyTexSubImage2D(target, level, xoffset, yoffset, x, y, width, height);
 
     return NS_OK;
 }