I have Samsung Galaxy Ace Duos S-6802 (originally Android 2.3). I followed the steps described here to update it. In short, I installed
ClockworkMod and then
JellyBlastGenED.signed in my phone.
After this update, My phone is showing Android v4.1.1 under settings. The icons, fonts etc are looking very small. Also my phone is not detecting any SIM and SD card as well. The phone is having two SIM card.
I just wanted to know that how can I undo the update or fix these errors?