Friday, March 29, 2013

Mod - Jiayu G2 Dual Core 1GB Jelly Bean 4.1.2 upgrade

Hi all,
as promised here you have a guide to successfully update your Jiayu G2 Dual Core 1GB Android ICS 4.0.4 to the latest version, that is Adroid Jelly Bean 4.1.2.

Before starting, I have to say that there are 2 different ways to update the phone, by recovery and by SP Tool.

My advice is to upgrade by SP Tools, to have a clean installation and avoid any kind of problem.

The SP Flashing Tool 

This said, let's start.

1) First of all, you have to download this:

It's basically the Flasher (updated to fix a UBOOT.bin issue with the JB 4.1.2 IPK) and the Jiayu driver folder.

2) Extract the archive on your desktop

3) Go to the extracted folder and enter the "USB VCOM Driver" folder

4) Select your Windows version and open the relative folder (if you have Windows 8, like me, the Windows 7 folder is the choice)

5) Once inside that folder, right click on the file according to the proper version of your Windows (x64 or normal).

6) Select "Install" from the menu

7) Select yes to the "not firmed driver" warnings and let Windows install the drivers

8) Now, with the driver installed, plug the USB cable to the computer and to the Jiayu and turn on the Jiayu (Note. this is not mandatory, but since Windows will install some more driver, just let it do it).

9) After this, unplug the usb cable from the Jiayu, open the back cover of the phone and remove the battery

10) Download this firmware (is the Official 4.1.2 from Jiayu. I've tried a lot of firmwares and as for now the one running better (and without weird Chinese apps) is the official one):

11) Extract the firmware on your desktop

12) Now go back to the SP Flashing tool folder (the first file you downloaded), right click on Flash_Tool.exe and "run as administrator" (dunno if it is needed on XP, I don't think so)

13) Once the program opens, click on the "Scatter-loading" button on the right

14) Locate the Firmware folder and select the scatter txt file

15) If you did everything good, the program should load the firmware without any error message

16) Once done, click on the "Download" button 

17) Now you have to be quick. Connect the usb cable to the Jiayu and quickly insert the battery

18) If you did it quickly enough, the program should start flashing the firmware. If not, redo the process

19) Once the flash is done, a green circle will be shown. You can unplug the Jiayu, remove the battery for some seconds and then put it back together with the back cover

20) Turn on the Jiayu and you will have the new firmware 

Note. Your phone will be in Chinese at this point.
To have it back in your language, just enter into settings and then scroll down looking for a small "a" image on the left. Once located, enter that menu and press the first option to select your language

Note2. All the firmwares listed here are only for the Jiayu G2 Dual Core 1GB mobile phone version. If you flash this firmware on a different version of the phone, you won't have the camera working or the phone won't boot at all.



  1. hi there!!
    I've used your method and everything went fine but...

    The wifi is not working anymore... is it normal??

    Thanks dude!

    1. did you check the phone version before flashing?

      After this guide Jiayu released 2 more versions. To check your version, download from the play store the app "Jiayu".


  2. I really want to do this to my G2, but it's a horrible download site that won't work here

    1. Here where? Mega is working like a charm in Spain and Italy...

    2. There is no Mac browser that I could find that will work with it. But it's ok, I'm using FF within a Windows VM on the Mac now and it's working.

  3. Also the wifi problem seemed to be a problem in Jellybean, affecting a lot of different devices.

    It's difficult to under the Jiayu app as it's in Spanish. There's lots of different things, I'm not sure what I'm downloading to be honest.

    If someone could post links here to the the latest Jellybean ROMS for G2 dual core would be great

  4. sorry meant difficult to understand

    1. The latest JB rom for G2 is the one posted.
      he guide is pretty easy to follow, nobody had an issue for this so far...

      I don't understand your issues.


    2. I don't have an issue... You said to someone else "After this guide Jiayu released 2 more versions. did you check the phone version before flashing?"

      Which implied there were more recent versions of JB for the G2 than the one you had posted.

      I've flashed phones and installed custom ROMS before, but that was for the ZTE Blade which had a HUGE and very good support community. It was impossible to go wrong.

      For the G2 there is ZERO community dedicated to this phone and what fragments of information there are, are scattered about the internet in places like your blog. It's best not to assume everyone just 'knows' how to get this to work without a problem.

      Also, I would be very interested to know if anyone has been able to overclock this model ? I have heard this is not easy with Mediatech chips.

    3. This comment has been removed by the author.

    4. That was referred to the mobile versions, not the ROM. There are different Jiayu G2 1GB revisions, but only one JB 4.2.1 official rom.


    5. Thanks. I need to keep reading, it's getting confusing. I couldn't get the usb2set_2kXP.inf file to run yet anyway. It just opens in Notepad.

    6. no! you have to go

      1. right click on computer icon
      2. Properties > Device manager > and you will find jiayu something..
      3. right click on it and click update driver..
      4. Browse my computer
      5. under search my driver.. you browse to that usb2set_2kXP.inf location and double click on it
      6. after browse it.. you click next.. if warning pop-up.. just (allow/install it anyway)
      7. finish.. now your USB will be working.. Good luck ^.^

  5. I give up with usb2set_2kXP.inf, it seems to do nothing when I right click: Install.

  6. i updated my Phone
    but the wifi signal is lost!
    i cant make connection with my wifi point

    before the update no problems!

    please support!

    1. Well, you should elaborate a bit more...

      Did you enter the wifi password again?

      Whenever you upgrade the phone by SP FlashTools, all the settings/info/data previously stored on the phone are lost.


  7. hi... how to unroot and go back to stock rom?? i already try framaroot it can't pls help me.... I want sent it to warenty

  8. Everything work fine on my phone .