diff --git a/src/xpra/client/gl/gl_window_backing.py b/src/xpra/client/gl/gl_window_backing.py
index 3cc11f9f03..041682432e 100644
--- a/src/xpra/client/gl/gl_window_backing.py
+++ b/src/xpra/client/gl/gl_window_backing.py
@@ -446,7 +446,7 @@ def update_planar_textures(self, x, y, width, height, img, pixel_format, scaling
             glActiveTexture(texture)
             glBindTexture(GL_TEXTURE_RECTANGLE_ARB, self.textures[index])
             glPixelStorei(GL_UNPACK_ROW_LENGTH, rowstrides[index])
-            pixel_data = img_data[index][:]
+            pixel_data = img_data[index]
             debug("texture %s: div=%s, rowstride=%s, %sx%s, data=%s bytes", index, divs[index], rowstrides[index], width/div_w, height/div_h, len(pixel_data))
             glTexSubImage2D(GL_TEXTURE_RECTANGLE_ARB, 0, x, y, width/div_w, height/div_h, GL_LUMINANCE, GL_UNSIGNED_BYTE, pixel_data)
             if index == 1: