The truth about the damaged phone font

Mobile phone font is originated from the Windows Mobile era, the so-called font is a close to the CPU near a very small flash chip, when the phone is mostly no operating system, mobile phone control information, font, etc. are cured to flash chip ROM, because the main part is the font, So the phone is fixed to the ROM title font.
and Flash chip is simply the memory chip in our USB flash drive, the storage function, this flash chip will not be lost due to power loss data, your USB flash drive data is not the same storage?
And now the Android phone so-called font IC, is not the previous Mount font information ROM, now the font IC is just a mobile phone boot for a moment, to the mobile phone hardware to guide the role, simple to say similar to the motherboard BIOS chip, "basic input and output system", with the motherboard BIOS, If you failed to brush the BIOS brush, your motherboard will be "brick", you need to get the motherboard to remove the BIOS chip, with the programmer to brush the BIOS. So now the motherboard has a double Bios,m_bios brush failed, B_bios top. The future of the mobile phone must also be a dual-font IC design, never change bricks.
Can card M defy on behalf of the Library IC has been led to complete, the system permissions can be given to the ROM, that is ROM thing, as for you can not enter the brush machine mode is also related to ROM.
If the font IC is bad, your cell phone is a standard brick, screen no display, no response to the button, everything is not any response, this is the font IC damaged brick signs, and for defy, the CPU and the library IC is the upper and lower layers of integration, so even if the brick has the same blind brush saved, Defy small white fake bricks, really brick looks really no, if who has defy brush dead "real brick", I cash collection, physical damage to the real bricks do not.
caused by the cell phone library IC damage, in addition to a few of their own quality problems, this probability estimate than you 500W is also low, for most of the current model, the only damage to the font IC is the confusion of the machine is the brush wrong font IC, and for defy, the font IC and the CPU is integrated, even if the same is the same as RSD Lite save, as to the principle of this, I think may be the core of Moto technology, we do not need to study, just need to know, our defy in addition to physical damage, it is impossible to change the real brick, to a lot of fake bricks.
The font is broken, is generally removed from the external direct connection to the font IC PIN, connected to the font with three-party device forced to brush, with the motherboard BIOS with the programmer to brush the BIOS, this is feasible, but replace the font IC I think is nonsense!
Change the mobile phone library IC on the equipment and welding technology requirements very high, I remember the country only Shanghai and Guangdong have this technology, other places simply can't change! Mobile phone changer IC is not a simple BGA soldering station can be done, let alone like defy this CPU and library IC integrated IC, this CPU and font integration IC chip do not say you have no equipment and crafts can be successfully replaced, that special IC you buy can not buy!
For Moto after-sales, if really is the font IC is bad, the cost of replacement of the whole board is better than the replacement of the Font IC, moto after-sale will not be with you to change the font IC, directly change version!
Real mobile phone chip-level maintenance is not much, the phone's BGA rework more difficult than the computer BGA, especially now the high-side integration of the circuit board, it is a face of the IC bad hard to put a face of the IC, B face the same position is mostly forced to suffer, now many mobile phone repair shop put a hot air gun, some also put a More than 10,000 BGA rework station, the vast majority of equipment for the show, the phone to true BGA repair, change version than BGA rework more cost-effective!! Can change the CPU to change the font IC less, can change like defy such a font CPU integration I estimate in addition to the Moto factory level, other people do not have this technology and equipment can change, even the Moto factory-level replacement, it is impossible to say 100% success, even if the chance to repair the repair is not small.
Font damage refers to the external computer program or rewrite ROM (that is, the brush) accidental power loss of the mobile phone ROM data deletion or modification, resulting in the phone system boot program can not start the situation, causing the font damage is generally the case of the two cases: rewrite ROM accidental power loss, resulting in the data is not completely brushed ROM, The phone fails to start, and another situation is that it can cause the phone to start failing by swiping the wrong data into the ROM.

Font, also known as Flash, Flash ROM flash read-only memory.

It loads the phone's basic program and various function programs in the form of code. So far the concept of the font is mixed, it is not clear, in the end what is the font?

We can actually differentiate between them and make them easier to understand.

Font, generally can be called Program memory (called program) and Chinese character Library memory (Word deposit), then why people do not call it?

This is because the previous mobile phone design when the Chinese font as a memory chip welding on the phone, the program memory version also as another storage welding and then mobile phone, and later developed to the program and the word storage compound together, so we call it a font.

The capacity of the font is much larger than the size of the chip, the common 32M 64 and 128M, and so on. The role of the font in the mobile phone is very important, the role of the following:

1 Storage Host Main program

2 Storage Font Information

3 Storage Network Information

4 Storing recordings

5 Storing encrypted information

6 Storage Serial Number (IMEI code)

7 Storage Operating System Flash

According to the operating voltage is divided into:

5V, 3.3V, 1.8V, 0.9V

By the data bus width is divided into:

8-bit data bus width

16-bit data bus width two kinds

By its bus and data are divided into:

(1) Bus and data bus separation

(2) Low 16-bit address bus and data bus merge

(3) Address bus and data bus merging

By its sector distribution is divided into:

TOP, bottom two kinds;

The package form is divided into:

TSOP40, TSOP48, FBGA48, UBGA56 FBGA72 BGA80 BGA69, etc.

According to its foot tube of how much, the phone's font can be divided into two major categories:

A class of 40-pin fonts (e.g. model 28f004,28f008)

Another type of 48-foot font (such as model 28f800,28f160f160, etc.)

The work flow of the font is rather complex:

When the phone is turned on, the CPU will be sent out a reset signal rest through the font, so that the system reset.

Again to the CPU to read and write the font, the selected end of the chip, the CPU can be removed from the font within the command,

In the CPU, the operation, decoding, the output of the coordination of the work of the command to complete their respective functions.

The software data of the font (FLASH) program storage is communicated with the microprocessor through the data exchange terminal and the address exchange.

CE (CS) end for the font chip select end, the OE end is read allow end, rest end is the system reset end, these four control end is controlled by CPU.

If the address of the font is incorrect or not selected, it will cause the phone to malfunction, usually shown as no boot, display character confusion and other phenomena.

Since the font can be used for erasing, it can be re-written with a programmer or a no-break machine repair device when data loss occurs.

and page numbers, the font itself may also be damaged (hardware failure), if the hardware fails, it is necessary to re-replace the font.

The largest feature of the font is erasable (can be programmed), the device relative to the previous EPROM program memory, the greatest advantage is that it can be programmed in the system (isp-insystemprogmmable), The simple point of this IAP technique is that a blank device on the circuit board can be programmed to write to the end user code without removing the device from the circuit board, and the programmed device can be erased or programmed in an ISP manner.

The general general practice is that the internal memory can be rewritten by the software of the host computer through the serial port.

For the microcontroller to be through the SPI or other serial acceptance of the host computer data and write to the memory.

So even if we solder the chip on the circuit board, as long as the host computer interface with this serial port, you can realize the chip memory rewrite, without having to remove the chip.

Said the popular point, is not to remove the font from the phone, you can use the computer with the transmission line to erase the font,

But different phones need to work with different tool software to complete the ISP (in the system programmable).

With the mobile phone function more and more, the mobile phone work program is also more and more large, the corresponding cell phone's font capacity is also more and more large.

For example, Motorola 328 English mobile phone font model is 28f800, the capacity of 1M bytes, addressing line width a0-a18 A total of 19 address lines.

When the Motorola V988, the addressing line width A0-a19 A total of 20 address lines.

and v988++ 's font model is 28f320, the capacity of 4M bytes, ground-seeking width a0-a20 A total of 21 address lines.

As the above example can be seen, the font of the address of the bus line width is increased with the font capacity, each more than a high-level address line, the capacity of the font increase by one times.

1, a new type of flash, such as 320c3b, in the general storage area behind the 128Bit of special encryption,

The first 64Bit (8 bytes) is the unique Device code (64BitUniqueDeviceIdentifier), each font is shipped with the factory,

And the same font model will not have the same code, even if the font is a new blank font.

Later, the 64Bit is a user-programmable OTP unit (64BitUserProgrammableOTPCells), which can be set by the user for personal use only and cannot be erased.

2, there are some mobile phones such as Siemens, NEC, etc., is the use of 64Bit unique code for encryption,

(1) Before the production of mobile phones, all the contents of the font are written uniformly.

(2) After the completion of mobile phone production, post, self-test to determine the unique code, and according to the unique code number, in the regular storage area to write the corresponding information, so the factory phone font is completely different.

(3) Mobile phone manufacturers This practice is to protect their own property rights are not subject to illegal plagiarism.

(4) Many maintenance workers have also tried to take a normal use of the mobile phone font to take down, read the information and write a new font, and put back to another phone, even if the same phone above, also can not be used normally, for example, Siemens is showing two lines of English. The reason is that the phone after the boot to determine whether the font's unique code and the main storage area of the corresponding, if not correspond to the display error message.

3, as a normal maintenance method, you can use some tools to find the unique code of the secret.

If using Linkchem lk48,up48, choose the type of "LOCK" or "-mlock", such as 320c3ock, you can read the unique device code and the user-programmable OTP unit,

And then through the comparison and other methods to find the method of decryption, but generally speaking, brush machine very few brush bad font

The truth about the damaged phone font