I have iGO Primo running under Android 2.3.5 on an Simvalley SPX-5. This is the same phone model as the teXet TM-5200, BLU Studio 5.3, UMEOX X1. When I turn the phone to landscape, the map stays in vertical direction. Also the iGO buttons und iGO information bars don´t switch - the android status bar does. Other apps switch to correct landscape mode, too.
I deinstalled iGO, deleted sys.txt and data folder, reinstalled - nothing ...