Courtesy of XDA we finally know the location of Jtag pin location of variety of Nokia Lumia, HTC and Samsung Windows Phone devices. We have included pictures of the Jtag pin, along with the dump and repair boot.
Samsung SGH-T899M and GT-I8750
DUMP : http://free-downloads.z3x-team.com/9…GH-T899M/Dump/
Repair boot :
http://free-downloads.z3x-team.com/9…-T899M/Repair/
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HTC 8S
Repair boot :
http://free-downloads.z3x-team.com/9…910000/Repair/
HTC 8X
DUMP: http://free-downloads.z3x-team.com/9…_PM23220/Dump/
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NOKIA Lumia 520
Repair boot :
http://free-downloads.z3x-team.com/9…ia_520/Repair/
Nokia Lumia 620
Repair boot:
http://free-downloads.z3x-team.com/9…ia_620/Repair/
Nokia Lumia 720
DUMP : http://free-downloads.z3x-team.com/9…umia_720/Dump/
Repair boot :
http://free-downloads.z3x-team.com/9…ia_720/Repair/
Nokia Lumia 820
Repair boot :
http://free-downloads.z3x-team.com/9…ia_820/Repair/
Nokia Lumia 920
Repair boot :
http://free-downloads.z3x-team.com/9…ia_920/Repair/
Nokia Lumia 925
Repair boot :
http://free-downloads.z3x-team.com/9…ia_925/Repair/
Nokia Lumia 1020
DUMP : http://free-downloads.z3x-team.com/9…mia_1020/Dump/
Repair boot :
http://free-downloads.z3x-team.com/9…a_1020/Repair/
The Jtag pins are useful for recovering your windows phone device if you are not able to recover it from errors like QHSUSB_DLOAD and so on.