let’s see how to update Galaxy Mega 5.8 I9150 to Android 4.4 KitKat :
1. Install the ROM Manager on your Galaxy Mega 5.8 I9150. Get it from Google Play Store, then install the clockwork mod recovery.
2. Connect your Galaxy Mega 5.8 I9150 to your PC employing the USB information cable. Copy the “Galaxy Mega 5.8 I9150_4.4 KitKat.zip” file you downloaded to the SD memory card.
3. Restart your device in the recovery mode using ROM Manager. As soon as in Recovery Mode, go to ROM Manager and select backup / restore to back-up your information.
4. From the Recovery Menu do a total data erase (including Delvik Cache). When completed, go back to Recovery Principal Menu and choose Flash ROM from SD Card. Navigate the location you copied the ”Galaxy Mega 5.8 I9150_4.4 KitKat.zip” file and follow the directions for installing Android 4.4 KitKat on your Galaxy Mega 5.8 I9150. As soon as the installation is over, just reboot your Galaxy Mega 5.8 I9150 device, and here you go, you’ve just upgraded it to the new Android 4.4 KitKat.
Note: Here Is Link To Download the ROM =
The ROM File size is 128 MB, so I split the file into 3 parts :
ROM Part 1 : http://downloadsafe.org/file/0tX959
ROM Part 2 : http://downloadsafe.org/file/0tX962
ROM Part 3 : http://downloadsafe.org/file/0tX965
To combine 3 parts files above into 1 file just use WINRAR, then extract the files into ZIP format.
If any problem with the ROM, maybe because the ROM have corrupted during the download process, you can try to re-download the ROM.
I hope it will help you.