[Miscellaneous Android Development] kahafeez:
I have translated this guide to English for people who do not understand Vietnamese

Credits: Hung Cuong Do, Shyn, Thuyduong and everyone who has made/ shared this ROM

TESTED ON PANTECH SKY VEGA R3 aka IM-A850L

Dear All,

Pantech Sky Vega A850L is a great phone at an amazing price but unfortunately most of its help on the internet is in Vietnamese language. I have this phone running on Android 4.2.2 (using this guide you can change your Stock ROM to a Custom International ROM which will remove the 80 characters SMS Limit) and I wanted to update it to Kit Kat (4.4). There are many ROMs present here for this phone. I found a KitKat based Custom ROM with good rating here and thought of trying it.

This video also helped a lot. Though its not in English but from 1 minute and 20 seconds onwards it shows how to install a Custom ROM.

Your phone must be ROOTED. Follow this guide to root Pantech Sky Vega R3 aka IM-850L.

LIST OF FILES TO BE DOWNLOADED

Firstly download these files:

ROM (Version 8 updated 27th November 2014):

[size=2]
https://drive.google.com/file/d/0Bw8sn5jec1C3bXJJeklVV2kzdmM/view?pli=1
OR
https://vkl.box.com/s/xsin4svte57j3kxx0cb2[/size]

Baseband File: (According to your phone's model)

[size=2]
A850S: Firmware MODEM_IM-A850S_S0216310
https://drive.google.com/file/d/0BxveGwot73rCTkV1amFpVHVJR1k/view

A850L: Firmware MODEM_IM-A850L_S1233310
https://drive.google.com/file/d/0BxveGwot73rCYmZlem5JbXJDQkE/view

A850K: Firmware MODEM_IM-A850K_S0837310
https://drive.google.com/file/d/0BxveGwot73rCY0dDRU5TZ2Z4MVE/view

[/size]

Recovery:

[size=2]https://drive.google.com/uc?id=0B8i26sLklJ_mMU5la0hlTUMycVE&export=download[/size]

Drivers Fastboot:

[size=2]https://docs.google.com/file/d/0B8i26sLklJ_mMk1fRmlfcnFMcUE/edit
[/size]

INSTRUCTIONS:

1. Put the ROM Zip file and the Modem File in your phone and turn on USB Debugging at Settings > USB Debugging

2. Turn off your phone

3. Press the Volume Down button + Volume Up button + Power button. Choose Fastboot by pressing Volume down and then press power to select your choice

4. In Fastboot mode, install the drivers just downloaded from the link given above. Open the “IM-A850_Recovery_All in one_06-4-2013” folder and run “Install Recovery from Fastboot.bat”. Choose Option Number 8 which will install and launch “ClockWorkMod Recovery v6.0.2.8 for Jelly Bean”

5. In CWM, its a smart move to make a nandroid backup of your phone by selecting Backup and Restore> Backup (Be sure that there is about 4GB of free space in your internal storage otherwise backup would fail.)

6. WIPE DATA/ FACTORY RESET

7.. WIPE CACHE

8. ADVANCED > WIPE DALVIK CACHE

9. MOUNTS AND STORAGE > FORMAT CACHE

10. MOUNTS AND STORAGE > FORMAT DATA

11. MOUNTS AND STORAGE > FORMAT SYSTEM

12. INSTALL ZIP FROM SD CARD > CHOOSE THE ROM(ZIP) FILE [TAKES ABOUT 3-5 MINUTES]

13. INSTALL ZIP FROM SD CARD > CHOOSE THE MODEM(ZIP) FILE

14. On the Main Menu, when you will choose “Reboot System Now”, it will ask you that Stock Recovery will be flashed and Root Access will be lost. To tackle this, simply choose “++++Go Back++++” and then a “Fix Root” option will appear. Select this option and let the phone restart.

15. On the first start up, select English as the phone language.

What is working:

1. Bluetooth

2. GPS

3. WIFI

4. Camera at 13MP

5. NFC (not tested)

6. Pakistani Network Signals working (tested on Mobilink)

Not tested yet:

1. 3G (Data is working but I am not in a 3G service area)

2. NFC

SCREENSHOTS: