Mt65xx Preloader 2

[Pierpont Oldham]

AfterI followed this steps (I don't know where I went wrong, I must be somewhere) )when I power on my phone it shows two messages in the botom of the screen and last about 20 seconds and the it powers off.

When i go to hardware manager, i can only see Mediatek PreLoader USB VCOM (Android) (COM 5) when i select "show hidden devices". When i select Mediatek PreLoader USB VCOM (Android) (COM 5) it says: Device not connected or no connection.

make sure you have the vcom drivers instaled properly, take the battery out of your phone go to device manager on your pc put your fingers on power and volume up plug in your usb cable after a few seconds you'll see preloader vcom flash on your screen ,you have to click on it quickly or it dissapears then insert the drivers and thats it .If your on windows 8 or 8.1 the windows 7 drivers work but you have to disable the didgital signatures first just start up your pc in advanced mode and dissable the signatures and restart your pc when you insert the drivers a warning will come up ignore it you'll okay and thats it ready to use flash tools .

I wanted to flash the ROM as some of the ROM files got corrupted. However I have downloaded the necessary files as mentioned in your site, and the problem is about installing the drivers. I have checked the comps Device manager there it doens not show any of the drives of VOM or ADB drivers or SP drivers, even tired with show hidden devies, but none, however when the phone is in ON it shows as usual in my comp all the HDD etc. So when I try to flash the ROM it does'nt detect or show the device as connected. Therefore when clicking download F9 it does nothing?

The Android operating system on my Kingelon was purposely patched to report fake information about RAM and storage, there are also traces of cheating well known benchmark tools. Till now the evidences are in two files:

WARNING: Do not remove that files! Someones (here and here) reported that the phone was bricked after removing the changeram.xml file. It seems that the safe procedure is to edit the files with correct values.

No fear! It is normal to see just a few cores, because the others are almost always stopped. To see all of the 8 cores just launch some CPU hungry apps (as Antutu benchmark) and check again /prco/cpuinfo, you will see all the cores at work.

Devices based on the MT65xx chip can be put in Download Mode, a state in which the flash memory can be formatted and reprogrammed. To activate this mode: turn off the device, remove the battery, and connect the USB cable to a PC (removing the battery is not strictly required). A communication interface is activated just for a few seconds (2 or so), the MT65xx device will keep the communication interface alive longer (as long as required) if it detects a data flow from the PC (Example: from SP Flash Tool).

MS-Windows users can install the required drivers in the little time the device appears: start the Device Manager (from Computer properties), attach the USB cable and wait until the MT65xx Preloader appears, quickly right-click on it and provide the drivers you downloaded. Once the driver are installed, the preloader device is displayed as MediaTek PreLoader USB VCOM Port.

We used VRoot to gain root access, which is simple and effective. The only drawback is that the procedure leave some useless apps into the phone and the superuser rights management apps is in Chinese. Other people suggest to use Kingo Android ROOT, which is otherwise suspected to stole personal data when rooting.

So I tried VRoot, which is a Microsoft Windows program capable of rooting several phones using the USB cable. It seems that only recent versions are capable of rooting my device, I used 1.7.9.9730 Chinese version. The rooting went fine, the only drawback is that you will find some Chineese apps instelled on the phone, many are useless, just one is the superuser rigths management app, which is to be replaced with Superuser by ChainsDD.

In order to verify that root permissions are working, I installed the Terminal Emulator app by Jack Palevich. In the terminal I typed the su command (which is installed by the rooting process) and the Chinese app for superuser rigths management popped up asking for confirmation. The button on the right means Allow.

Afer rooting with VRoot we found three Chinese apps installed on the phone, one is used to manage superuser permissions, but we want to install SuperSU by Chainfire instead (we tried also Superuser by ChainsDD, but it was unable to automatically replace the Chinese counterpart). This is the procedure:

For the user applications, just open the app manager and uninstall them. For the system ones it is possibile tu use some uninstaller like App Master, which obviously requires root privileges. That application (at least v. 5.4.0) does not clean every trace of the app, it does not remove the /data/data// directory and the package section into /data/system/packages.xml file, so a manual method is better.

Another system app, which comes with the stock ROM, is the Google Pinyin Input Method (PinyinIME.apk), the Chinese name is 谷歌拼音输入法. This is an input method (keyboard) for Chinese language. Remove it if you don't want to write Chinese.

I tried to backup data using adb tool via the USB cable, but it fails if all the objects are included: the command never returns and the confirmation dialog on the phone does not dismiss as expected. I had to execute two separated backups:

The back camera takes pictures at about 13 Mpixels (4160 x 3120). While colors are quite satisfying, the quality is poor indeed. With default settings in good light conditions, the noise in midrange shadows is rather visible, compression artifacts are also annoying. It seems also that some sort of sharpening filter is applied automatically: zoom at 1:1 or more to see the exagerated contrast of fine details.

Sometimes the orange LED did not light-up when the power adapter was plugged; sometimes a crazy loop of messages charger plugged - charger unplugged begun, which can result in phone crash. Sometimes, when the phone was plugged for the nightly charge, the orange LED turned on, but the morning after the phone was completely discharged ad the LED was off. Sometimes applying a light force to the USB connector (blending it toward the back of the phone) seemed to help, but everything was extremly unreliable.

It was not a cable or connector problem, it turned out that the power connector required a soldering reflow. Fortunately only a partial disassemble of the phone was required: just removing the back frame you can detach the power board.

Remove the 10 screws which keep the back frame. Divaricate the metal-plated frame from the screen glass using your thumb's nails. Facing the screen: the glass comes toward you and the frames goes to the back. Beware of the volume and power buttons.

Now the power board is free and you can reflow the soldering. I put very little soldering flux over the contacts, a bit of tin (a good silver-alloy) on the soldering iron. I used a 2 mm soldering tip, larger than the contacts, so I used very few tin for a very short time. Clean the flux with a needle, cotton swab and alcohol; inspect closely to avoid short-circuits.

How to reproduce, possibility 1:

1. Disconnect the USB connection, if necessary.

2. Turn off the phone.

3. Connect the phone via USB. It will take a bit and then turn on, displaying the "charge animation".

Why does this happen? Luckily I've read the MediaTek Preloader source code. The Preloader is the first-stage bootloader on MediaTek SoCs and exposes a proprietary USB interface that can be used for debugging purposes and to download firmware to the device. The implementation of this interface is rudimentary and emulates a CDC ACM serial port, which probably doesn't fully conform to the standard and also just falls from the bus after a short amount of time if the host doesn't initiate the proprietary protocol. So I think the kernel and ModemManager immediately try to use the emulated device when it becomes available, but because the implementation in the Preloader is incomplete some bug (timeout?) is triggered and ModemManager never closes the device.

I'm hitting this exact same issue with a different device, it's a development board that communicates over USB CDC (an Adafruit Bluefruit Micro, a little bluetooth LE microcontroller board). The device has similar behavior as the mentioned MediaTek preloader where it implements a very basic USB CDC endpoint and can abruptly disconnect at times if for example it times out waiting for a response from the host computer.

Not sure what else I can add unfortunately to the discussion but your debugging info is super helpful to confirm this appears to be the same issue. I'm not familiar with ModemManager either but is there any way to rollback to an older version and pinpoint what change caused the issue?

Oh nice thanks for the workaround, just tried a similar udev rule and it seems to work great. Re-enabled modem manager service, applied the MM ignore value with a rule, and can see the /dev/ttyACM* port stays the same between resets of the device. We'll add it to udev rules we tell folks to use when using the hardware (rule is here if you're curious: _Arduino_Linux/blob/master/99-adafruit-boards.rules). Thanks!

This also solved my problem on a serial communication issue I was having with a GoPro Hero 3+Black camera over USB with a serial interface that enumerates as ttyACM device files. The Linux host was a Banana Pi running this build of Linux.

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