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[JTAG] HTC Topaz JTAG pinouts (unbrick)

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By the-equinoxe, Retired Moderator on 24th April 2010, 10:41 PM
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I purchased a drowned HTC Diamond 2 which I used to house my MDA V in.
Now I was in possession of a broken mainboard.
Since the JTAG pinouts are unknown till this date, I stripped the mainboard from all its components and traced the board in order to find the JTAG.
Had to make new probes from some needles in order to trace from the BGA-Grid..
The difficulty here was that the test-pins where on the other side as where the MPM 7200-A was, and with those tiny bga-vias it was real hard to trace.

Some pictures of the board (before stripping)
The front side of the Mainboard (it is a single board device, apart from speakers, LCD and antenna no further external parts, all on one board!)

Backside with foil still on it (this side is facing the front of the device)

Backside without Foil and here are the JTAG testpins:

The Pins I traced:

*other pins:
Mode 0 (between TRST-N and TDI)
Will be checking for other pins on request (btw: sofar watchdog, mode 1,2,3 are not (yet) found)

These should suffice to JTAG the device.

For those in need of testpoints for reference voltage etc..:

Other info:
Memory module (on this board):

More info Regarding JTAG as being used to debrick HTC Dream


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25th April 2010, 12:01 AM |#2  
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Great work equinoxe!!
25th April 2010, 12:26 AM |#3  
the-equinoxe's Avatar
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Originally Posted by orb3000

Great work equinoxe!!

Well thanks for the board in the first place, without it I wouldn't be able to trace the pins!


25th April 2010, 05:47 AM |#4  
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Sounds interesting, could you explain what this could be used for?

25th April 2010, 07:23 AM |#5  
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one use for JTAG is to flash the device at a low level (i.e. lower than the bootloader) - one use for this method of flashing is that you can recover from a bad bootloader flash

There are plenty of other uses too, that's just one
25th April 2010, 02:34 PM |#6  
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Kewl! I didn't know that
25th April 2010, 10:08 PM |#7  
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Red face :)
Very informative
25th April 2010, 10:14 PM |#8  
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Very good work, the first step to a device picking up momentum in a modding community is to find the JTAG pins, nice!
26th April 2010, 08:16 AM |#9  
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is this something awesomely awesome?
i mean does it enable us to do something cool which we couldnt do before?
26th April 2010, 01:09 PM |#10  
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You can eg. repair a hardbricked device.
Since you are entering the device on a lower level than the bootloader.
Lots of possibilities.

26th April 2010, 06:48 PM |#11  
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so, could this be used to enable iSecretary to work as a genuine answeringmachine? To send audio directly and not through speaker? And record incomming, ofcourse.
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brick, bricked, debrick, diamond 2, jtag, mda v, pure, topaz, unbrick

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