diff --git a/src/calibre/ebooks/oeb/profile.py b/src/calibre/ebooks/oeb/profile.py
index 032fe5e5ff..e1fdcff13f 100644
--- a/src/calibre/ebooks/oeb/profile.py
+++ b/src/calibre/ebooks/oeb/profile.py
@@ -50,7 +50,7 @@ PROFILES = {
                 fsizes=[12, 12, 14, 16, 18, 21, 24, 28]),
 
     'CybookG3':
-        Profile(width=584, height=754, dpi=168.451, fbase=16,
+        Profile(width=600, height=800, dpi=168.451, fbase=16,
                 fsizes=[12, 12, 14, 16, 18, 21, 24, 28]),
 
     'Kindle':