JTAG HTC Wildfire S

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JTAG HTC Wildfire S

The HTC Wildfire S is an Android based smartphone. At the time of this writing (2012MAR30) I am unaware of any method to bypass the PIN, password, or pattern locks on a HTC Wildfire S that is not rooted and does not have ADB enabled. JTAG to the rescue! Using JTAG, a copy of the NAND can be extracted, and the pin or pattern lock decoded from it.

For the purpose of this document, a Virgin Mobile HTC Wildfire S was disassembled, read via JTAG, reassembled, the pattern lock changed, and the process repeated. This process was done to get 2 reads from the device with different pattern locks each time. The first pattern lock was set to represent a "T" character while the second pattern lock was set to represent a "C" character.

Getting Started

What you need to extract the lock from the device:

  1. A RIFF Box with the latest JTAG Manager software. The RIFF Box used for this was purchased from http://www.multi-com.pl.
  2. HTC Wildfire S JTAG adapter (or soldering skillz). The adapter used for this was purchased from http://www.multi-com.pl.
  3. A DC Power supply capable of supplying 3.7V/1.3A output. The power supply used for this was an Agilent U8002A DC Power Supply.
  4. PatternLockScripts from CCL Forensics ('GenerateAndroidGestureRainbowTable.py' and 'Android_GestureFinder.py').

NAND Dump Procedure

  1. Disassemble the phone down to the PCB.
  2. Connect the RIFF Box to the PCB via USB.
  3. Connect the RIFF Box to the PCB via the JTAG adapter.
  4. Connect the RIFF Box to the PC via USB.
  5. Connect the PCB to the DC power supply.
  6. Start the "JTAG Manager" software and configure.
  7. Power the PCB.
  8. Dump the NAND.

Instructions for disassembly can be found on Internet but it can be summarised as follows:

  1. Remove the rear cover and battery.
  2. Remove the Torx and Phillips screws.
  3. Split the phone case using a case opening tool (guitar pick).
  4. Disconnect the 3 tiny ribbon cables (tweezers on either side).
  5. Remove the PCB.

You are now ready to connect the PCB to the RIFF Box and the RIFF Box to the PC. See the pictures for more detail. Note: The JTAG adapter indicates pin 1 on the top of the PCB with a small dot (covered by the rubber band in these pictures).

Riff-to-htc-wildfire-s-connection-1.png Riff-to-htc-wildfire-s-connection-2.png
Riff-to-htc-wildfire-s-connection-3.png

Now we can start the RIFF Box JTAG Manager software and configure it. See the picture for more detail.

Riff-box-settings-annotated.png

Connect the PCB battery terminal connections to the DC power supply. The negative (-) connection is the innermost PIN and the positive (+) pin is the outside PIN.

Apply power to the DC power supply and turn the phone on using the tiny little button on the ribbon cable attached to the top of the PCB. After powering the phone on, start the NAND dump by clicking the "Read Memory" button in the JTAG Manager software. The NAND dump read needs to be started shortly after the phone is powered on. Once the NAND read is complete you can click on the "Save" button to save the binary dump to a file.

If you receive errors that the PCB could not be connected to, try the following:

  • Confirm that the PCB is receiving power from the DC power supply. If you can measure current draw of the PCB, you should see that the PCB is pulling about 0.07A. If the PCB is pulling more current, it is likely already booted and the read may fail.
  • Power off the PCB, power it back on, and immediately start the JTAG Manager read.
  • Check the JTAG adapter to ensure it is correctly orientated and that all the pogo pins are touching the PCB JTAG pads.
  • Recheck the JTAG to PCB connections.
  • Upon receiving a successful JTAG dump you can process the file with the CCL Forensics Android scripts to extract the gesture or pin lock.

References