I'm copy paste this tutorial from forum.xda-developers.com :
The Galaxy Mega 5.8 I9150 owners may also want to keep their device up-to-date. So we thought of giving you a tutorial of how to upgrade Galaxy Mega 5.8 I9150 to Android 4.4 KitKat. With new version of android operating system on your device, you will have more benefit. Your device will have more feature, more secure, more fast performance, and more cool he...3x. But prior to telling you how to install Android 4.4 KitKat on Galaxy Mega 5.8 I9150, let’s see what do you want in order to be able to perform the installation. You will have to download 4.4 KitKat Galaxy Mega 5.8 I9150 ROM. You will also have to root your Galaxy Mega 5.8 I9150 to prepare it for Android 4.4 KitKat upgrade. Discover how to root Galaxy Mega 5.8 I9150 and install Android 4.4 KitKat from here. Here are the download links of the files you want to update Galaxy Mega 5.8 I9150 to Android 4.4 KitKat. Just before beginning to upgrade your Galaxy Mega 5.8 I9150 to Android 4.4 KitKat don’t forget to backup your information, as contacts, text messages and the apps installed from Google Play Store who maybe lost when the installation finishes. Now 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://goo.gl/7pyL97
ROM Part 2 : http://goo.gl/ffHU2x
ROM Part 3 : http://goo.gl/l1zKh5
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.
Thank you for visiting Upgrade/Update Galaxy Mega 5.8 I9150 to 4.4 KitKat
Tutorial Video to Download ROM :
Tutorial Video to Download ROM : by Michael
