VS
for Strap Boot device:
1.Procesor (VCCORE) rail voltage 0.9 V-1.5V
2.Ram (VCCRAM) Voltage 1.8V rail for DDR2, DDR3 VTT 1.5 V to 08V-0, 99V
3.Vga chips and input / output control, hub chip (VCCP) 1.5v rail voltage, 1.8 V, 3v
1.Procesor (VCCORE) rail voltage 0.9 V-1.5V
2.Ram (VCCRAM) Voltage 1.8V rail for DDR2, DDR3 VTT 1.5 V to 08V-0, 99V
3.Vga chips and input / output control, hub chip (VCCP) 1.5v rail voltage, 1.8 V, 3v
VS to Device (Lcd / led,
hdd, optical, usb, wifi, bloutooth, keyboard, sound, camera etc.) For details
on each Rail Voltage VS can be seen in the schema and Datasheet motherboard and
components as well as the device in question.
Signal the wave triger /
Sensor / 2-way confirmation signal / data interface
signal function open / close gate charge of organizing stages enable / disable each component or PCI (Peripheral commucition interface). Microcontroller System signal is governed by where the manufacturer has made a firmware binary command to set logic gate interface and low count pin into each IC bios on each motherboard.
signal function open / close gate charge of organizing stages enable / disable each component or PCI (Peripheral commucition interface). Microcontroller System signal is governed by where the manufacturer has made a firmware binary command to set logic gate interface and low count pin into each IC bios on each motherboard.
Differences sircuit and arrangement on the motherboard of course require different settings Microcontroller, so that each of each different motherboard brand and series firmaware will necessarily require different settings.
This system can accept input signal, process it and deliver the output signal in accordance with the program in the contents into it.Microcontroller input signal derived from the sensor information from the environment (discrete) while the output signal addressed to the actuator (an electronic circuit for moving or controlling a mechanism or system) then give effect to the environment.
The microcontroller can easily analogized as the brain of a device / product that is programmed to be able to interact with the surrounding environment, embedded system is often referred to as the control systems that are embedded in a product.
Embedded System can not stand Alone
Microcontroller need to trigger the CPU clock oscillator working on one instruction to the next instruction in microcontroller operation time of one or several clock cycles to run.
There are several types of memory found in the microcontroller, ROM (ReadOnly Memory) and RAM (Random Access Memory). ROM is used as storage firmware while in modern electronic circuit use type EPROM (Erasable Programmable Read Only Memory) and EEPROM (Electrical Erasable Programmable Read Only Memory). CPU, memory, clock oscillator, and I / O are in one integrated circuit. If some elements omitted, then the system can not work.
Unlike the simple Embedded controller, microcontroller on sircuit LaptopMotherboard more complex embedded systems which have an external rom called the BIOS IC separate even they actually are part inseparable
Power
States (S0-S5)
The System Power
States are often referred in the AMT documentation. This blog post attempts to explain
the various System Power States (S0-S5).
The overall power
consumption of the system is referred to as System Power States. There are a
total of six different power states ranging from S0 (the system is completely
powered ON and fully operational) to S5 (the system is completely powered OFF)
and the States(S1, S2, S3 and S4) are referred to as sleeping states, in which
the system appears OFF because of low power consumption and retains enough of
the hardware context to return to the working state without a system reboot.
The key
characteristics of the eachstate that we care about are:
§ The overall Power the system
consumes in a given state - Power Consumption.
§ Retention of the system context
(such as the volatile registers, memory caches, and RAM) - Context
Note on power
state transition: System is Waking Up when the system is transitioning from the
OFF State (S5) or any sleep state (S1-S4) to the ON State (S0) and the System
is going to Sleep when the system is transitioning from ON state (S0) to OFF
state (S5) or sleep state (S1-S4). Please note that the system cannot enter one
sleep state directly from another, as it must enter the ON state before
entering any other sleep state.
§ System Power State S0 the ON
state: The system is completely operation, fully powered and completely retains
the context.
§ System Power State S1 the Sleep
state: The system consumes less power than S0 state. All Hardware &
Processor context is maintained.
§ System Power State S2 the Sleep
state: The system consumes less power than S1 state. Processor loses power and
processor context and contents of the cache are lost.
§ System Power State S3 the Sleep
state: The system consumes less power than S2 state. Processor & Hardware
context, cache contents, and chipset context are lost. The system memory is
retained.
§ System Power State S4 the
Hibernate state: The system consumes the least power compared to all other
sleep states. The system is almost at an OFF state, expect for a trickle power.
The context data is written to hard drive (disk)and there is no context
retained.
§ System Power State S5 the OFF
state:The system is in a shutdown state and the system retains no context. Note
that in power state S4 the system can restart from the context data stored on
the disk, but in S5 the system requires a reboot.
Global
states
§ G0 (S0): Working
§ G1, Sleeping subdivides into the four states S1
through S4:
§ S1: All processor caches are
flushed, and the CPU(s) stop executing instructions. Power to the CPU(s) and
RAM is maintained; devices that do not indicate they must remain on may be
powered down.
§ S2: CPU powered off
§ S4: Hibernation or Suspend to Disk. All content of main memory is saved to non-volatile memory such as a hard drive, and is powered down.
§ G2 (S5), Soft Off: G2 is almost the same
as G3 Mechanical Off, but
some components remain powered so the computer can "wake" from input
from the keyboard, clock, modem, LAN, or USB device.
§ G3, Mechanical Off: The computer's
power consumption approaches close to zero, to the point that the power cord
can be removed and the system is safe for dis-assembly (typically, only the real-time clock is running off its own small
battery).
Furthermore, the
specification defines a Legacy state: the state
on an operating system which does not support ACPI. In this state, the hardware
and power are not managed via ACPI, effectively disabling ACPI.
Device states
The device states D0-D3are
device-dependent:
§ D0 Fully On is the operating state.
§ D1 and D2 are intermediate power-states whose
definition varies by device.
§ D3 Off has the device powered off and
unresponsive to its bus.
Processor states
The CPU power
states C0-C3are
defined as follows:
§ C0 is the operating state.
§ C1 (often known as Halt) is a state where the
processor is not executing instructions, but can return to an executing state
essentially instantaneously. All ACPI-conformant processors must support this
power state. Some processors, such as the Pentium 4, also support an Enhanced C1
state (C1E or Enhanced
Halt State) for lower power consumption.[7]
§ C2 (often known as Stop-Clock) is a state where
the processor maintains all software-visible state, but may take longer to wake
up. This processor state is optional.
§ C3 (often known as Sleep) is a state where the
processor does not need to keep itscache coherent, but maintains other state. Some
processors have variations on the C3 state (Deep Sleep, Deeper Sleep, etc.)
that differ in how long it takes to wake the processor. This processor state is
optional.
Performance
states
While a device or
processor operates(D0 and C0, respectively), it can be in one of several power-performance
states.
These states are implementation-dependent, but P0 is always the
highest-performance state, with P1 to Pn being
successively lower-performance states, up to an implementation-specific limit
of n no greater than
16.
P-states have
become known as Speed Step
in Intel processors, as Power Now !or Cool 'n' Quiet
in AMD processors, and
as Power Saver
in VIA processors.
§ P0 max power and frequency
§ P1 less than P0, voltage/frequency
scaled
§ Pn less than P(n-1),
voltage/frequency scaled
MICRO
CONTROLLER
Microcontroller
is a microprocessor system SET contained in a chip. Contains components
of the system supporting the microprocessor, memory and interface provider
(interface) Input output controller, the difference with the microprocessor usually
only contains the CPU alone. (Except Sandybridge CPU).
Significant
difference between microprocessor and microcontroller is, a microprocessor CPU
(Central Processing Unit) with no memory and I / O support, while the
microcontroller consists of a CPU, memory, I / O specific and supporting units,
for example Analog to Digital Converter (ADC) that have been integrated in the
microcontroller.
This
system can accept input signal, process it and deliver the output signal in
accordance with the program in the contents into it.
Microcontroller
input signal derived from the sensor information from the environment
(discrete) while the output signal addressed to the actuator (an electronic
circuit for moving or controlling a mechanism or system) then give effect to
the environment.
Easily
the microcontroller can be analogized as the brain of a device / product that
is programmed to be able to interact with the surrounding environment, as
prescribed by the microcontroller .The system is often referred to as embedded system
control systems that are embedded in a product.
Embedded
System can not stand Alone
Physically,
the workings of a microcontroller can be described as a cycle of reading
instructions stored in memory. Microcontroller will determine the address of
the program memory to be read, and the process of reading the data in its
memory. Then the data is read interpreted as a command called the program
counter.
Microcontroller
need to trigger the CPU clock oscillator working on one instruction to the next
instruction .Each small step from microcontroller operation time of one or
several clock cycles to run.
There
are several types of memory found in the microcontroller, ROM (ReadOnly Memory)
and RAM (Random Access Memory). ROM is used as a storage media program while in
modern electronic circuit use type EPROM
(Erasable Programmable Read Only Memory) and EEPROM (Electrical Erasable
Programmable Read Only Memory). CPU, memory, clock oscillator, and I / O are in
one integrated circuit. If some elements omitted, then the system can not work.
On
this note I will discuss how the application of a microcontroller on the board
circuit especially on laptop motherboards.
Unlike
the simple Embedded controller, microcontroller on circuit Laptop Motherboard
more complex embedded systems which have an external rom called the BIOS IC
separate .even they actually are part inseparable.
EC
bios as Embedded firmware controlling Power management and other controls
in accordance with the programming commands that are already regulated by
inter-IO interface available with programming sircuit The difference
arrangement will cause the system to malfunction.
The
storage capacity of the ROM is also much larger so that programming is more
detailed and complex to do.
Almost
the entire System switching on Laptop motherboard governed by this system, even
microcontroller in the system can perform the switching stage 5 at the same
time , known as Sleep State.
Microcontroller
can receive input ADP + as a command VALW standby on Line Power major in circuit,
the input signal is set based command programming so that if the signal input
(adapter current detector) recorded in accordance with a range of programming,
the EC will allow ADP + entry into circuit and when the input detects Excessive
analogue system will propel ground to deter entry into ADP + sircuit and enable
OVP (over voltage protection)
Embedded
systems are also set based on the input signal when to instruct perform laptop
battery charging system, this signal is usually referred to BAT_IN and active
when the battery is installed, this detection will give the order to make the
filling by sending a signal CHG_Enable Charger IC.
Embedded
systems are so much involved in laptop motherboard, they set up almost the
entire input-output communication interface in circuit.
Beginning
with a switching system in which the EC receives signals EC_ON for Embedded
activated controlling and turn signal VS (State enabled) then sends a
signal to activate the gate driver power state based on pre-defined sequence.
Bios chip as
firmware storage to run microcontroller
Modern Laptop circuit have
2 Bios Chip to stored separated Embedded controller firmware and PCH
(southbridge) Firmware .
EC Bios rom size usually smaller than Main Bios, This Bios chip stored a firmware to run micro controller on Embedded controller (SIO) this firmware controlling Power management including switching system and Sleep state .
Embedded controller is a computer inside the chip ,to get runing this EC need firmware that we call EC bios file (firmware).Signal confirmation power OK name RSMRST.
EC Bios rom size usually smaller than Main Bios, This Bios chip stored a firmware to run micro controller on Embedded controller (SIO) this firmware controlling Power management including switching system and Sleep state .
Embedded controller is a computer inside the chip ,to get runing this EC need firmware that we call EC bios file (firmware).Signal confirmation power OK name RSMRST.
EC bios
controlling Power management and other controls in accordance with the
programming commands that are already regulated by inter-IO interface available
with programming sircuit The difference arrangement will cause the system to
malfunction. The storage capacity of the ROM is also much larger so that
programming is more detailed and complex to do.
Almost the entire System switching on Laptop motherboard governed by this system,
Microcontroller can receive input ADP + as a command VALW standby on Line Power major in circuit, the input signal is set based command programming so that if the signal input (adapter current detector) recorded in accordance with a range of programming, the EC will allow ADP + entry into circuit and when the input detects (over voltage protection)and shoot down the entire system.
Embedded systems are also set based on the input signal when to instruct perform laptop battery charging system, this signal is usually referred to BAT_IN and active when the battery is installed, this detection will give the order to make the filling by sending a signal CHG_Enable Charger IC .
Embedded systems are so much involved in laptop motherboard,
they set up almost the entire input-output communication interface in circuit.
Beginning with a switching system in which the EC receives signals EC_ON from switch button, Embedded activated Southbridge by giving switching signal and turn signal VS (State enabled) then sends a signal to activate the gate driver power state based on pre-defined sequence.
Beginning with a switching system in which the EC receives signals EC_ON from switch button, Embedded activated Southbridge by giving switching signal and turn signal VS (State enabled) then sends a signal to activate the gate driver power state based on pre-defined sequence.
See the diagram
below to get more detil :
Main Bios is a firmware to
run Southbridge most main function are running LPC Bus interface.
with the programming commands that are already regulated by inter-IO interface available with programming circuit The difference arrangement will cause the system to malfunction. The storage capacity of the ROM is also much larger so that programming is more detailed and complex to do.
with the programming commands that are already regulated by inter-IO interface available with programming circuit The difference arrangement will cause the system to malfunction. The storage capacity of the ROM is also much larger so that programming is more detailed and complex to do.
There are
2 ways to measuring Bios chip IC ,EC Bios storage EC or SIO firmware having
power on S5 state ,it's mean ones adapter plug in this voltage will present , Vcc
pin is main supply voltage for 3.3V the
other pin need 3.3V supply is Pin 7 and pin 3 .if one of this voltage missing
EC will not able to access the firmware bios from this IC ,Pin 4 is ground and
others pin direct to EC or SIO
How Main Bios connected to PCH here :
Main Bios
is a firmware for Southbridge,This Southbridge (PCH) need a firmware to run
properly to controlling Low pin count (LPC) and controlling communication
interface with EC-PCH-CPU and Graphic Chip .Signal confirmation power ok name
PLT_RST#.
Knowing Bios Chip
and how they work
Bios Chip
BIOS (Basic input output system)
Serial Flash memories provide a storage solution for systems with limited space,
pins and power. The 25X series offers flexibility and performance well beyond ordinary Serial Flash devices. They are ideal for code download applications as well as storing voice, text and data. The devices operate on a single 2.7V to
3.6V power supply with current consumption as low as 5mA active and 1μA for power-down.
All devices are offered in space-saving packages.
The W25X10A/20A/40A/80A array is organized into 512/1024/2048/4096 programmable pages of 256-bytes each. Up to 256 bytes can be programmed at a time using the Page Program instruction.
Pages can be erased in groups of 16 (sector erase), groups of 256 (block erase) or the entire chip (chip erase). Erasable sectors and 2/4/8/16 erasable
blocks respectively. The small 4KB sectors allow for greater flexibility in applications that require data and parameter storage.
Supports the standard Serial Peripheral Interface (SPI), and a high
performance dual output SPI using four pins: Serial Clock, Chip Select, Serial Data I/O and Serial Data Out. SPI clock frequencies of up to 100MHz are supported allowing equivalent clock rates of 200MHz when using the Fast Read Dual Output instruction. These transfer rates are comparable to those of 8 and 16-bit Parallel Flash memories.
A Hold pin, Write Protect pin and programmable write protect, with top or bottom array control.
There are
several physical model of Bios IC ,they marked by amount of soket pin .
new motherboard model usually use SO 8 Bios IC ,there 2 kind of SO 8 marked by size 200ml and 150ml
Bios IC have several capacity : 256MB~512MB~1MB~2MB~4MB ~8MB and 16MB.identified capacity of bios chip by marking kode by look at the end of valuable code :
Example : 25xxx08 = 1MB ,25xxx16= 2MB,25xxx32= 4MB,25xxx64 = 8MB.
Persistent BIOS infection
"Persistent BIOS infection", is a method presented in Can Sec West Security Conference (Vancouver, 2009) and SyScan Security Conference (Singapore, 2009) where researchers Anibal Sacco and Alfredo Ortega, from Core Security Technologies, shows error code insertion into the decompression routines in the BIOS , allowing for nearly full control of the PC in any start-up, even before the operating system boot.
Proof-of-concept does not exploit a flaw in the BIOS implementation, but only involves the normal BIOS flash procedure. Thus, it requires physical access to the machine or to the user in the operating system to be root. Despite this, however, researchers underline the profound implications of their discovery: "We can patch the driver to make a fully working root kit. Has even a small code that can remove or disable antivirus in bios rom.
Changing bios chip / reprograming / erase / backup / updated bios
After understanding the bios chip , functions and how it works can be understood if the bios corupted / crashes or there is a bug / virus / data error in bios , can cause the entire motherboard or partly paralyzed can not work ( totally dead ) .
EC bios that can still boot up go into bios settup / hank on logo or are still able to get into windows enough to just do an upgrade on latter bios version .
Download programe run the exe file , follow the next command in the updater program that has running don't forget to ensure battery and adapter attached . Low power while updating process updated bios will fail .
Can not go in / boot windows , updating bios can do by booting through dos bootable flash disk. Several different way on each different brand and series .example for acer aspire one boot bios updated by using the fn + esc key , Compaq laptop using windows key + B and toshiba laptop using ctrl + U key .
If the updater fails on both the above methods , flashing with erase / delete the data and replace the old bios / flashing new data or if the bios chip using Bios eprome programer.
Modern motherboards of Laptop have 3 kind of Bios
1, Main bios is that we usually find in general the motherboard to control the basic input output system on SB/NB/VGA Instrumental in setting chipsets (ICH-PCH-SB-NB) ... Bios Bug can cause the chipset can not function properly. This firmware managed all chip interface communication.
2. EC Bios (embedded controller bios). EC firmware bios related to the main bios and save settings for embedded controller chip .This firmware managed all power signal management include GPIO/SM_BUS/Keyboard controller including system switching signal, password security controller (see datasheet for more detail EC Fiture)
3.ID Bios which only store data to determine information about motherboard ID.
Bios IC has a ROM to save EC Bios firmware for SIO/EC microcontroller management. This work like a computer inside the IC's. SIO managed all signal, stepping sleep state thermo controller ,protecting error etc.(get the detil info download the Datasheet)
Even whole component onboard ok and power well will stop working if EC Bios Firmware damage .
To check Firmware ok ,there is a signal test confirmation on EC/SIO pin name RSMRST# .This pin must available 3.3V(tolerance 10%) than Bios Confirmed OK.
Check the power need also Bios IC and SIO need 3.3V powered VCC for working well
new motherboard model usually use SO 8 Bios IC ,there 2 kind of SO 8 marked by size 200ml and 150ml
Bios IC have several capacity : 256MB~512MB~1MB~2MB~4MB ~8MB and 16MB.identified capacity of bios chip by marking kode by look at the end of valuable code :
Example : 25xxx08 = 1MB ,25xxx16= 2MB,25xxx32= 4MB,25xxx64 = 8MB.
Persistent BIOS infection
"Persistent BIOS infection", is a method presented in Can Sec West Security Conference (Vancouver, 2009) and SyScan Security Conference (Singapore, 2009) where researchers Anibal Sacco and Alfredo Ortega, from Core Security Technologies, shows error code insertion into the decompression routines in the BIOS , allowing for nearly full control of the PC in any start-up, even before the operating system boot.
Proof-of-concept does not exploit a flaw in the BIOS implementation, but only involves the normal BIOS flash procedure. Thus, it requires physical access to the machine or to the user in the operating system to be root. Despite this, however, researchers underline the profound implications of their discovery: "We can patch the driver to make a fully working root kit. Has even a small code that can remove or disable antivirus in bios rom.
Changing bios chip / reprograming / erase / backup / updated bios
After understanding the bios chip , functions and how it works can be understood if the bios corupted / crashes or there is a bug / virus / data error in bios , can cause the entire motherboard or partly paralyzed can not work ( totally dead ) .
EC bios that can still boot up go into bios settup / hank on logo or are still able to get into windows enough to just do an upgrade on latter bios version .
Download programe run the exe file , follow the next command in the updater program that has running don't forget to ensure battery and adapter attached . Low power while updating process updated bios will fail .
Can not go in / boot windows , updating bios can do by booting through dos bootable flash disk. Several different way on each different brand and series .example for acer aspire one boot bios updated by using the fn + esc key , Compaq laptop using windows key + B and toshiba laptop using ctrl + U key .
If the updater fails on both the above methods , flashing with erase / delete the data and replace the old bios / flashing new data or if the bios chip using Bios eprome programer.
Modern motherboards of Laptop have 3 kind of Bios
1, Main bios is that we usually find in general the motherboard to control the basic input output system on SB/NB/VGA Instrumental in setting chipsets (ICH-PCH-SB-NB) ... Bios Bug can cause the chipset can not function properly. This firmware managed all chip interface communication.
2. EC Bios (embedded controller bios). EC firmware bios related to the main bios and save settings for embedded controller chip .This firmware managed all power signal management include GPIO/SM_BUS/Keyboard controller including system switching signal, password security controller (see datasheet for more detail EC Fiture)
3.ID Bios which only store data to determine information about motherboard ID.
Bios IC has a ROM to save EC Bios firmware for SIO/EC microcontroller management. This work like a computer inside the IC's. SIO managed all signal, stepping sleep state thermo controller ,protecting error etc.(get the detil info download the Datasheet)
Even whole component onboard ok and power well will stop working if EC Bios Firmware damage .
To check Firmware ok ,there is a signal test confirmation on EC/SIO pin name RSMRST# .This pin must available 3.3V(tolerance 10%) than Bios Confirmed OK.
Check the power need also Bios IC and SIO need 3.3V powered VCC for working well
ACPI
(Advanced Configuration and Power Interface) power management
ACPI is defined as a platform interface to the hardware detection, monitoring power management configuration. Determining the multiprocessor specification and Plug and Play devices. Besides power management aims to conserve power by stopping the power supply when not in use. Stages are controlled by the embedded operating system or known as Bios firmware file.
This firmware is executed with SPI Flash (Flash memory) electronic storage media that can be erased and reprogrammed electrically. (EEPROM electrically erasable programmable read-only memory). Firmware this only works when run on the same circuit that has been in the program with Embedded controller and PCH were recorded.
This firmware is used to execute commands Basic input output system by sending a signal switches on the command input (trigger) S5_ON at SIO or embedded controller then forwards the order to the PCH (south bridge) switching system that activates the power supply to the Processor , Memory, Graphic Chip and others.
BIOS IC
There are several physical model of Bios IC ,they marked by amount of soket pin .
new motherboard model usually use SO 8 Bios IC ,there 2 kind of SO 8 marked by size 200ml and 150ml
Bios IC have several capacity : 256MB~512MB~1MB~2MB~4MB ~8MB and 16MB.identified capacity of bios chip by marking code by look at the end of valuable code :
Example : 25xxx08 = 1MB ,25xxx16= 2MB,25xxx32= 4MB,25xxx64 = 8MB.
Persistent BIOS infection
"Persistent BIOS infection", is a method presented in Can Sec West Security Conference (Vancouver, 2009) and SyScan Security Conference (Singapore, 2009) where researchers Anibal Sacco and Alfredo Ortega, from Core Security Technologies, shows error code insertion into the decompression routines in the BIOS , allowing for nearly full control of the PC in any start-up, even before the operating system boot.
Proof-of-concept does not exploit a flaw in the BIOS implementation, but only involves the normal BIOS flash procedure. Thus, it requires physical access to the machine or to the user in the operating system to be root. Despite this, however, researchers underline the profound implications of their discovery: "We can patch the driver to make a fully working rootkit. Has even a small code that can remove or disable antivirus in bios rom.
Changing bios chip / reprograming / erase / backup / updated bios
After understanding the bios chip , functions and how it works can be understood if the bios corrupted / crashes or there is a bug / virus / data error in bios , can cause the entire motherboard or partly paralyzed can not work ( totally dead ) .
EC bios that can still boot up go into bios setup / hank on logo or are still able to get into windows enough to just do an upgrade on latter bios version .
Download programe run the exe file , follow the next command in the updater program that has running don't forget to ensure battery and adapter attached . Low power while updating process updated bios will fail .
Can not go in / boot windows , updating bios can do by booting through dos bootable flashdisk. Several different way on each different brand and series .example for acer aspire one boot bios updated by using the fn + esc key , Compaq laptop using windows key + B and toshiba laptop using ctrl + U key .
If the updater fails on both the above methods , flashing with erase / delete the data and replace the old bios / flashing new data or if the bios chip using Bios eprome programer.
ACPI is defined as a platform interface to the hardware detection, monitoring power management configuration. Determining the multiprocessor specification and Plug and Play devices. Besides power management aims to conserve power by stopping the power supply when not in use. Stages are controlled by the embedded operating system or known as Bios firmware file.
This firmware is executed with SPI Flash (Flash memory) electronic storage media that can be erased and reprogrammed electrically. (EEPROM electrically erasable programmable read-only memory). Firmware this only works when run on the same circuit that has been in the program with Embedded controller and PCH were recorded.
This firmware is used to execute commands Basic input output system by sending a signal switches on the command input (trigger) S5_ON at SIO or embedded controller then forwards the order to the PCH (south bridge) switching system that activates the power supply to the Processor , Memory, Graphic Chip and others.
BIOS IC
There are several physical model of Bios IC ,they marked by amount of soket pin .
new motherboard model usually use SO 8 Bios IC ,there 2 kind of SO 8 marked by size 200ml and 150ml
Bios IC have several capacity : 256MB~512MB~1MB~2MB~4MB ~8MB and 16MB.identified capacity of bios chip by marking code by look at the end of valuable code :
Example : 25xxx08 = 1MB ,25xxx16= 2MB,25xxx32= 4MB,25xxx64 = 8MB.
Persistent BIOS infection
"Persistent BIOS infection", is a method presented in Can Sec West Security Conference (Vancouver, 2009) and SyScan Security Conference (Singapore, 2009) where researchers Anibal Sacco and Alfredo Ortega, from Core Security Technologies, shows error code insertion into the decompression routines in the BIOS , allowing for nearly full control of the PC in any start-up, even before the operating system boot.
Proof-of-concept does not exploit a flaw in the BIOS implementation, but only involves the normal BIOS flash procedure. Thus, it requires physical access to the machine or to the user in the operating system to be root. Despite this, however, researchers underline the profound implications of their discovery: "We can patch the driver to make a fully working rootkit. Has even a small code that can remove or disable antivirus in bios rom.
Changing bios chip / reprograming / erase / backup / updated bios
After understanding the bios chip , functions and how it works can be understood if the bios corrupted / crashes or there is a bug / virus / data error in bios , can cause the entire motherboard or partly paralyzed can not work ( totally dead ) .
EC bios that can still boot up go into bios setup / hank on logo or are still able to get into windows enough to just do an upgrade on latter bios version .
Download programe run the exe file , follow the next command in the updater program that has running don't forget to ensure battery and adapter attached . Low power while updating process updated bios will fail .
Can not go in / boot windows , updating bios can do by booting through dos bootable flashdisk. Several different way on each different brand and series .example for acer aspire one boot bios updated by using the fn + esc key , Compaq laptop using windows key + B and toshiba laptop using ctrl + U key .
If the updater fails on both the above methods , flashing with erase / delete the data and replace the old bios / flashing new data or if the bios chip using Bios eprome programer.
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