Windows Phone 7.5  users were almost frustrated at the announcement of Windows Phone 8 because they wont get updated to WP8. However, Microsoft surprised everyone with WP 7.8, bringing several features of WP8 to them. After months of anticipation, update has finally started rolling out, and Nokia Lumia series is the first to get the update. For the rest of the devices the update won’t be rolled out in the near future, but you can go ahead and try this safe method which requires a simple desktop tool .

Instructions

1. If all goes well, you won’t lose any of your device data, but back everything up just to be on the safe side.
2. Connect your Mango phone to your computer via USB. This will launch Zune but if it doesn’t show up, launch it manually.
3. Head to the ‘Settings’ section in your phone’s menu (in Zune, and not on your phone itself), and click the ‘Update’ option from the sidebar.
4. If the update is officially available, you don’t need this guide at all; simply proceed with updating the phone using the instructions provided in Zune from there. Otherwise, close Zune.
5. The next steps will involve pushing new CAB files to your device. For that, download the WP7 Update Cab Sender and extract the contents of the downloaded zip file to a folder on your computer.
6. Now head to this XDA forum thread to grab the firmware files and language pack(s). There is no distinction between firmware for different carriers and devices. This means you will miss out on any carrier-specific changes of the update that might be coming in the future. You’ll need to grab the OS files for versions 7.10.8779.8 and 7.10.8858.136, while skipping the 7.10.8783.12 file.
7. There are a lot of language files available at the link provided in the previous step and the only way to identify them is by a language code that is part of their name. For everyone looking to get the English (U.S) version of Windows Phone 7.8, the required code is 0409. Simply press CTRL+F and search for the code to arrive at the desired link. To get the codes for other languages, visit the link at the end of this post. You’ll need to download the relevant language files for both 7.10.8779.8 and 7.10.8858.136 versions.
8. Now that you have all the necessary files downloaded to your computer, unzip them all and put all files for version 7.10.8779.8 in the folder where you extracted the Cab Sender tool, keeping the files for version 7.10.8858.136 in a different folder for now.
9. Make sure your device is connected to the computer & Zune is not running, and launch the Cab Sender tool.
10. Once your device has been detected, press ‘B’ to proceed.
11. Now just let Cab Sender do its job. The tool will reboot your phone multiple times, and you will get a notification on the device when the update is complete.
12. Your job isn’t done yet; the above procedure has to be repeated for the version 7.10.8858.136 files as well. To do this, remove all files for version 7.10.8779.8 from Cab Sender’s folder, copy the files for version 7.10.8858.136 to it, and go through steps 9, 10 and 11 once again to install version 7.10.8858.136.

That’s it. If you can’t believe that you really do have Portico on your device, head to the ‘about’ section of the Settings menu and check OS details. Even if you face any errors while applying this method, Cab Sender is smart enough to leave your device in the condition you started the procedure in.