Questions tagged [jtag]

JTAG, short for Joint Test Action Group, is a method used for boundary scanning. Possibly applications are hardware testing/debugging and firmware flashing, including debricking of hardware which ended up in a defunct state.

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How can I differentiate the JTAG pins like TMS, TDI, TDO, & TCK using impedance

How can I differentiate between the JTAG pins like TMS, TDI, TDO, & TCK using impedance? Because when we connect JTAG (RS422) with unnamed pin, we got a problem. So I am asking how to identify ...
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How can I identify JTAG in this case and utilize it?

I'm developer and I somehow tried today to reverse engineer and take apart a hardware, just after learning that some devices have hardware debugging. First thing to try to know in my understanding of ...
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WRT54GL firmware extraction via JTAG with OpenOCD and Raspberry Pi as interface. Can not dump because the device is not halted

Good day! Sorry to come up with something very old. Since I am currently teaching myself hardware hacking, I wanted to use my old router for this. I soldered pins to the JTAG interface and connected ...
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Help required to figure out the JTAG or UART pins

I have an old CDMA dongle lying around, so I thought to try to reverse engineer them, but am unable to figure out the UART or JTAG pins, I have attached a photo of the probable pins, can anyone help ...
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3 votes
2 answers
910 views

How do I extract the firmware from this bluetooth speaker board?

I have a bluetooth speaker. Infinity Fuze 100. It's a good speaker. But it has annoying messages on startup and shutdown. And for other interface events. I'd like to either get rid of them entirely, ...
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Dump Headunit Software

I am a computer engineering senior and have a few quick questions i couldn't find any hits about online. I know just enough to get myself into trouble. Note: I have no specialized tools just a DMM and ...
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cheap BGA x-ray machine?

I want to look under a BGA chip and map JTAG pins to traces where I can attach a JTAGulator. Is there some version of a BGA x-ray that isn't thousands of $'s? Here's a picture of the BGA's. Would it ...
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JTAG TCK on Intel X Scale (ArmV5) PXA270

Is TCK on JTAG the same speed as CPU clock on a Intel X Scale (ArmV5) PXA270? I'm probing signals on pads around the CPU and got a waveform like: But I don't know whether any of this data is JTAG, or ...
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ARM 20-pin JTAG header?

I'm trying to find the JTAG header for an Intel X Scale (ArmV5) PXA270 board. I found and populated a 20-pin header: but JTAGulator doesn't think it has a valid combination of TDI/TDO/TMS/TCK on ...
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1 answer
435 views

NAND flash programming over host MCU JTAG

We starting mass production of a custom device. It uses Chinese MCU LT1901. MCU core is arm926ej-s. MCU boots from NAND flash. We are forced to program NAND flash before soldering on PCB. I don't like ...
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JTAG Dumped Flash is scrambled

I dumped the flash memory of an old ARM9 Chip running VxWorks using the SEGGER J-Link and the savebin command from J-Link Commander. Here is an example of a line of HTML stored on memory. <!DOC^...
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3 votes
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What is an "mpi register base"?

For the past few months, I have been using my spare time reverse engineering a set top box that will not be named. I am trying to run a media server or use it as a debian desktop. It is rocking a ...
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Finding the function of test points on a router

I have a BCM3383 based cable router here where I ultimately want to dump the firmware. I have serial access to the broadcom bootloader and the linux console. Login for linux is unkown and telnet does ...
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1 vote
1 answer
587 views

JTAG protection bypass

When protecting a device from being accessed via JTAG there are a number of ways to do it. The two that come immediately to mind are: a 'fuse' that is blown; a JTAG 'password'. What are some ...
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How to identify SWD (Serial Wire Debug) pinout?

When trying to access firmware, JTAG and SWD can be really helpful to the reverse engineer. When looking at an unknown board/device tools such as JTAGEnum or JTAGulator are really helpful in ...
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Finding JTAG/UART Connections

I need help identifying the UART or JTAG connections on this board. I would like to dump the firmware using a pirate bus.
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Writing data flash of MPC5606B through JTAG interface using Nexus

I'm programming flash memory of MPC5606B through JTAG interface using Nexus. I'm imitating a tool that perform this task. However, in the middle of the process, the entire flash memory is erased. I ...
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Extracting Keyboard Firmware

I am trying to find out how to extract firmware from a Bluetooth keyboard, my understanding is that I would have to JTAG to retrieve the the firmware from the device is that correct? Also has anyone ...
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Can JTAG and memory protections be glitched over? (regarding silicon construction of a micro)

Glitch method: irrelevant for topic of conversation, assume clock injection, voltage glitch, EMFI, "lasers", whatever you like. Device: For example modern ARM or PPC, or MIPS micros. Assuming you can ...
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Flash reading by JTAG in MPC5606B

I'm using MPC5606B and I would like to know what kind of issues I would have, concerning protection\encryption if I tried to read its flash content by JTAG using an external device. I was able to ...
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7 votes
2 answers
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Flash Reading by JTAG

I'm trying to read the flash memory of a microcontroller MPC5606B from Motorola. I saw his pins and saw that it uses jtag to perform debug, so I'm trying to use it JTAG interface to read its flash ...
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2 votes
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MSP430 JTAG FUSE

I'm using MSP430 micro controller which support physical fuse for jtag. The problem is I have blown the physical fuse so I can't interact with the controller, is there any way that I can interact with ...
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1 answer
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How to convert the dumped firmware (from linksys-wrt54gl via JTAG port) in an understandable format

Issuing some commands for the dumped firmware: $ du -h fw.bin 4.0 M $ file fw.bin fw.bin: data $ file -i fw.bin fw.bin: application/octet-stream; charset=binary $ binwalk fw.bin - $ enca -L none ...
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Help identify missing component for jtag connection

I found JTAG header for ARM (OMAP3x). It's a Cortex 10-pin 0.05" JTAG/SWD Connector. (See here) I think it's JTAG because PIN#3 and 5 are on GND and it's close of CPU When I follow the wires, TCK, ...
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Solve problem with debugging Linksys-wrt54gl with JTAG using BusPirate programmer

I am getting this output when I am issuing this command: $ sudo openocd -f board/MyBuspirate.cfg -f board/linksys-wrt54gl.cfg Open On-Chip Debugger 0.10.0+dev-00092-g77189db (2017-02-25-13:44) ...
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Trying to dump firmware from embedded flash

I have an Infineon XC161CJ-16F SoC and Micron/ST M29W320EB parallel nor flash memory that I am trying to dump the firmware from but I'm not sure how to proceed. I found JTAG pads that I soldered pins ...
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2 votes
2 answers
666 views

Call function in remote (OpenOCD) target from gdb

Is there any way to call a function on a remote target that's attached via JTAG? Currently I have OpenOCD hooked up to a target and I'm attached with gdb, and I know the address of the function I want ...
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2 votes
2 answers
268 views

I need advice on how to JTag a Microsoft Band

I am studying Computer Forensics in at a university in the UK and for my final year project, I wanted to combine my love of Microsoft products and Computer Forensics to see what kind of information a ...
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3 votes
1 answer
794 views

Is it possible to run a flash memory dump from a production device inside of an emulator/simulator?

I am not sure if this is the right forum, or if it would be better suited in a different SE sub, though I figure this is an appropriate place for it. I am wondering if there are any emulators that ...
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2 votes
0 answers
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JTAG finding BS registers for IC's pins

On the internet, it always shows that each pin of the IC has its own Boundary Scan register (the yellow boxes) But looking at BSDL files there are actually more BS registers than pins. So for the ...
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OpenOCD, Buspirate JTAG reads fail after short time

I have a board that I'm reversing - and attempting to dump the image out of the NAND flash. Board has a SAMSUNG s3c2440 SOC CPU, and there's a SAMSUNG k9f1g08u0d 128 MB NAND flash device. I'm using ...
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Using USB JTAG probe with ARM & MIPS

Can someone advice USB JTAG probe designed for both ARM and MIPS target boards, and which works with the OpenOCD and UrJTAG? I know Flyswatter2..
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10 votes
1 answer
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Breaking in and debugging an unknown Arduino program

Okay, so I've got an Arduino which has a sketch flashed to it (that I do not have source code for) which I'd like to reverse-engineer, and I've successfully dumped the flash and disassembled part of ...
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8 votes
1 answer
2k views

GDB via JTAG on ARM Hardware target without source code

Does anyone have other solutions for connecting to a remote ARM target without IDA? This is the question and below I give examples of setup's i have tried, should anyone be interested. Update: ...
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9 votes
2 answers
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Connecting to jtag-openocd-gdb to arm11 device with IDA gets no control

I have a binary chunk from a piece of hardware I've been deciphering with IDA for a couple days now. Today I finally got a probe connected via JTAG and have openocd start up a GDB server. IDA is ...
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7 votes
1 answer
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Using MIPS EJTAG functionality in OpenOCD

I am trying to use the OpenOCD functionality of a BusBlaster to debug a MIPS target. However, it doesn't look as though my target MIPS chip is defined in the list of sample target chip configurations -...
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30 votes
4 answers
32k views

How do I identify and use JTAG?

I'm a software guy through and through. But periodically when I'm taking apart hardware I know to look for JTAG ports and RS232 ports. So far I've always been lucky and have been able to solder on ...
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