Jiayu G2S - "unofficial forum"

“Unofficial” Guide to Flashing the Official Jiayu G2S ROM


Pre-requisites:

• You need a PC running Microsoft Windows 2000 or higher.
• If you haven’t previously installed msxml 6.0 and .net Framework 4.0 or higher on you Windows PC, do so first. Get them directly from Microsoft. (I assume you know how to search.)

Download the following:

• Latest Jiayu G2S ROM update; the rom I installed was the G2s_20130109-104044 stock rom: http://pan.baidu.com/share/link?shareid=157669&uk=839171988 (Note: the build number of the ROM after installation is: G2S 20130108-104044; don't be confused by the name of the file.) Use Google Translate if you need to see which button to push to start the download. Also note that there is a newer official rom for newer versions of the phone. The rom date is 20130306. I don't know what happens if you install the newer version on an older phone.
• This zip file contains the Android USB driver, VCom drivers, SP Flash Tool, and a document of these instructions (ReadMe.doc): http://www.mediafire.com/?tc4q3wy5eabowhf

Unzip the files you downloaded and move/copy folders and files where they need to go:

• Within the rom zip that you downloaded from the Baidu website, you can find the \G2s_20130109-104044 sub-folder. This folder contains the actual rom files (14 files). Move this entire folder onto your desktop. The reason for doing this is that there are folders within the zip file whose names contain characters that your version of Windows might not be able to read, even if you can see them in Windows Explorer (the filemanager). This will cause you trouble when you try to flash the rom.
• After unzipping the driver and flash tool zip file, you will find the \USB-VCOM-Drivers folder with \INF and \SYS sub-folders. In the \INF folder there are three other sub-folders: \ 2K_XP_COM, \Vista, and \Win7.

1. Copy the \INF\cdc-acm.inf file into your C:\Windows\inf folder. (You may have to give permission to do this.)
2. Based on your version of Windows (2K-XP, Vista, Win7, 32-bit or 64-bit), locate the one correct usb2ser_????.inf file and copy it to your C:\Windows\inf folder. (You may have to give permission to do this.)
3. Copy both the \SYS\androidusb.sys and \SYS\usbser.sys into your C:\Windows\System32\driver folder. (You may have to give permission to do this.)

Install the drivers:

• Plug your phone into your computer with a USB cable. If you had not previously installed the drivers, the system will start trying to install them.
• If the system asks you to choose to install the drivers, click on “install the software automatically” and proceed.
• If system is unsuccessful in locating and installing the drivers, you can try to go back and locate the drivers yourself by pointing to the individual files, but this should not happen if you properly copied the drivers over to your C:\Windows system folders.

BACKUP YOUR DATA NOW!

• Proceeding beyond this point is going to mean that EVERYTHING on you phone is going to be deleted and a new system will replace it.
• You have been warned!

Warning!

• Attempting to install a rom that does not use the correct “scatter” file (see description below) will brick your phone. Don’t do it. If you aren’t sure a rom is made for your phone, don’t attempt to install it.

Install the updated ROM:
1. Turn off your phone, open the back, and remove the battery.
2. Plug your USB cable into your PC and phone. If your PC attempts to install drivers, let it finish.
3. Unplug your phone from the cable.
4. Start the SP Flash Tool program by clicking on the Flash_tool.exe file. If you get a security warning, allow it to run.



5. Click on the “Scatter-loading” button on the right side.
6. Browse to your \Desktop\G2s_20130109-104044 folder and choose the MT6577_Android_scatter_emmc.txt file. All other files will be chosen automatically.



7. Click on the “Firmware -> Upgrade” button.
8. Plug your USB cable firmly into the phone. The Flash Tool will automatically start flashing your new rom. Wait for it to finish and show you the green circle.



9. Unplug your phone from the cable.

Rebooting the phone:
1. Install your battery.
2. Very carefully, without touching the screen, push the power button.
3. Do not touch the phone as it boots!
4. After it has completed booting, you may again use your phone normally.

JIAYU G2S

The Jiayu G2S was released on January 1, 2013. It was a significant upgrade to the G2 with a lot of hardware changes. For the price, it had an impressive list of specifications:

• MTK MT6577T ARMv7 Cortex-A9 Dual-core 1.2GHz processor
• GPU: PowerVR SGX531
• 4 inch QHD IPS screen, 960x540 pixel display, OGS (One Glass Screen)
• Dual SIM cards supporting GSM 850/900/1800/1900mhz & WCDMA 3G 2100mhz network (only one 3G slot)
• 1GB RAM / 4GB ROM
• Supports up to 32gb class 12 microSD card (TF card)
• 8MP rear camera, 2MP front camera
• Supports WiFi a/b/g & WiFi hotspot, Bluetooth with EDR & A2DP, GPS & AGPS
• Android 4.1 OS (Jelly Bean), multi-language
• FM Radio
• Gravity Sensor, Proximity Sensor, Light Sensor, Magnetic Sensor, Gyroscopic Sensor
• 2200mah battery
• Size: 125 x 61x 9.9mm
• Weight: 145g with battery

Overall, I really like the look and feel of the phone. Except for the ear speaker hole, the front is one solid piece of glass, wrapped around with a very solid metal frame. The metal frame is not just a thin piece of sheet metal, but is cast metal, provides for complete rigidity for the whole phone, and should do a good job of protecting that large piece of screen glass. This also means that the phone has a bit of weight, but that feels good in my hand. Additionally, I like the more rectangular design of the phone and the more square edge down the sides that the flat metal frame provides. It is very easy to hold onto.

Call quality is very good for me. Reception seems on par with other phones I've used. The wifi might be a bit weaker than my Huawei G300, but it is fine. The screen is very nice to look at and very sensitive, but you should read below about the "jump screen" problem. You should also read below about potential problems with GPS connection issues. I've now owned two of these phones. The first had the jump screen problem, and was replaced under warranty. The replacement has terrible GPS pickup, but no jump screen problem.

The large battery means that I have no problem getting through a day of use, and I probably could use it for two days without a charge most of the time. (But I do not use the phone for gaming.) The phone runs most of the time at 1001mhz or 250mhz when on, and will only jump to 1200mhz in extreme conditions. "Deep sleep" mode is for when the screen is off, but the phone will run at 1001mhz when charging no matter if it is on and being used or not. That is an issue for phones based on this MTK chipset and not exclusive to the JY G2S.

Jiayu includes a few apps targeting the Chinese market for this phone, but other than that, the OS is mostly "vanilla" Android Jelly Bean (AOSP). The phone comes already rooted, so freezing or deleting unwanted apps is a simple solution for what you don't want. There are a number of modified roms available already, including the Lewa rom (http://www.needrom.com/phone-roms/jiayu/g2s/). But you should note that later hardware versions of this phone have different components. You should make a note of what the rom version is that came installed on your phone so that you know what hardware version you are using.

"Jump Screen" Problem Solved?:
Many of the first batch of phones were plagued with screen problems. Commonly referred to as the "jump screen" problem, the result is that when scrolling through screens of data, the screen just "jumps" to a different location without any apparent reason. The screen also "quivers" when touching it, even if you aren't moving your finger. Jiayu promptly acknowledged the problem and tried to correct it with a quick ROM update released on January 9, 2013. (The build number of the ROM is: G2S 20130108-104044.) This ROM update did seem to work for some, but for others the problem persisted.

At this point, I personally don't know if the problem has been completely solved in the manufacturing of subsequent batches of the phone. My phone had the problem, and flashing the new ROM did not solve it. I returned the phone for replacement under warranty and did receive a replacement phone that does not have the problem. So whether or not there still is a manufacturing problem, Jiayu can replace the phone with one that works. However, see below for the GPS connection problem that I now have.

GPS Connection Problems:
There are also a number of users here who are reporting difficulty with weak GPS fix. My GPS fix on my first phone was excellent, but my replacement phone is not good at all. It has been suggested to install "Faster GPS" from the Play Store, which will let you set your location. Also, you can look at this post from later in this thread for more information: http://xdaforums.com/showpost.php?p=39975417&postcount=209. (Please post any solutions you discover in this thread.)

ROM Flashing:
One of my initial struggles was getting the official rom flashing tool to work. I finally got things going, and I hope I can help others who "just don't get it". So if you want some detailed instructions in English for how to flashing a new official ROM onto the Jiayu G2S, have a look at the second post. (If you are flashing a third-party rom, follow the rom builder's instructions.)

ClockworkMod Recovery:
"Thingbreaker" has provided us with a working CWM Recovery. Here's his post link: http://xdaforums.com/showpost.php?p=37521066&postcount=28
There are two ways to flash the CWM Recovery image: using the ROM flashing tool (harder) or using Mobileuncle Tools (easier).

• To use Mobileuncle Tools, install it from the Play Store (free). Copy the CWM Recovery image file to the root of your SD card, making sure there are no spaces in the filename. Run Mobileuncle Tools and choose Recovery Update. Choose the recovery image file that Thingbreaker provided.
• To use the ROM flashing tool, you first you need to understand how to flash a complete rom as explained in the second post of this thread directly below. After you know how to do that, then look at this post to learn what is different about only flashing the recovery image: http://xdaforums.com/showpost.php?p=37499848&postcount=23

Conclusion:
I do not recommend purchasing this phone. Period. Until Jiayu can do a better job of quality control, I don't recommend their products. There are other companies out there who's phones are only slightly more expensive, but who have a much better reputation for quality control.

Jiayu, if you are reading this, you need to do better! And you really need to improve your repair department as well. Sending me a replacement phone with a GPS problem causes me to wonder if you are using the "shuffle" method of passing around bad phones instead of repairing them. I'm NOT a satisfied customer.

My G2S has a problem with GPS signal too. After reading this thread I decided to try hardware mod.
First of all I dismantled the phone. Its very easy to do. All you need is one very small philips (PH 0) screwdriver and piece of hard and thin plastic (I used plastic knife)

Remove 6 screws on the back and open back cover with plastic knife. GPS antenna is on the top right corner. It looks like copper foil with some glue to keep it in place. Here is the photo:



I am 100% sure that one is for GPS because my phone couldnt find any satellite signal for almost 30 minutes.
To remove it you must carefully peel it of from every corner. When you finish external side you must peel of its connector on internal side of back cover. Once everything is free it is easy to take it out. Another photo:





Than I made test antenna from thin aluminium foil for kitchen use. This was just temporary antenna because the foil is very thin, sensitive and difficult to fix in right place. I am looking for thicker alu or, even better, copper foil for permanent solution.
It looked like this:



and internal side of back cover:




There is no special reason for this shape of antenna. I dont have any knowledge about design or required parameters. I just took a scissors and cut the shape that seemed logical at that moment. I am sure that the result and accuracy will be much better if someone made right design.

Both test were done on same spot - on my window. The weather was nice and clear.
First, test with original antenna. You will notice the time - this was filmed after I made my alu-foil antenna because I couldnt wait ti try it so I forgot to record the performance with factory antenna. Anyway, here it is:


It couldnt lock more than 5 satellites or reach more than 15m accuracy.


Now, take a look how it works with my design:


Frankly speaking, I am very surprised with the difference. If someone wants to recommend a better shape I will be happy to test it once I find suitable material. Actually, I can try to make it again from same thin foil but I dont guarantee that I will be able to reach exact measures.

here is my CWM Recovery, it's work on my device.
DWYOR


you can flash it with SPflashtool, or mobile uncle tools [root]

Links for G2S (how to First post & second post)

SP Flashtool + Drivers + Scatter
SP Flashtool(3.12) + Drivers + Scatter G2S
Drivers Windows 8x64
Newer flashtool (v3.1316.0)
Drivers G2S

Recovery's
Stock Recovery (mega)
CWM 6.0.1.5 (dropbox)
CWM 6.0.1.5 (mega)
CWM 6.0.2.8 (mega)
TWRP v.2.4.1.0 (dropbox)
TWRP v.2.5.0.0 (mega)

ROM's
G2S JB - 20130109-104044 ROM SP & CWM
20130109-104044 SPFlash G2S (mirror link)
20130109-104044 SPFlash G2S (official link)
20130109-104044 CWMFlash G2S (mirror link)
20130109-104044 CWMFlash G2S (official link)

G2S JB - 20130306-143807 ROM SP & CWM
20130306-143807 CWMFlash G2S (mirror link)
20130306-143807 CWMFlash G2S (official link)
20130306-143807 SPFlash G2S (mirror link)
20130306-143807 SPFlash G2S (official link)

Patch
Redlight Deep Sleep bug (Flash through recovery)
20130109 better auto-brightness & redlight fix G2S
20130306 better auto-brightness & redlight fix G2S

Other
Lewa OS (EN/CN) (official link)
Gapps for Lewa OS)
Needrom(official link)
592zn.com Chinese forum G2s
Jiayu official forum G2s
Jiayu official product pageG2s