mohamed you don't need to change firmware if stock menu in your MMC can exit to winCE desktop. Try to hold "settings" button in menu for a while. It should exit to desktop.
All you need after that:
1) Download last version of SingleMenu from here (free registration needed to download):
http://4pda.ru/forum/index.php?showt...ost&p=33241142
you can also contact there with main developer CrazyDron about English translation and installation of navigation program you wanted.
2) Copy SingleMenu folder on SD-card, then open it on MMC and launch main exe-file.
It will work until full-reboot of MMC. Drivers for working of GPS dongle and rear camera already included in this menu.
3) Buy USB GPS dongle like this:
http://www.aliexpress.com/item/VK-17...252525519.html
Any rear camera:
http://www.aliexpress.com/af/rear-ca...atId=200004828
For camera connecting you need mini-ISO to RCA cable like this:
http://www.aliexpress.com/item/Blaup...269592952.html