Difference between revisions of "Kenwood TH-D74A"

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**Hardware attack - Remove Flash Memory and read directly (possibly encrypted)
 
**Hardware attack - Remove Flash Memory and read directly (possibly encrypted)
  
−
Initially the radio was opened and wires were soldered to test points and a port of interest as seen in the video below.
+
Initially the radio was opened and wires were soldered to some test points and an interesting PCB footprint that I suspected was JTAG as seen in the video below.
  
 
<youtube width="320" height="240">EZP2DVU9IvQ</youtube>
 
<youtube width="320" height="240">EZP2DVU9IvQ</youtube>
 +
 +
There is also a serial port labeled SCTX and SCRX, both of these lines appear to be transmit only from the top CPU board down to the bottom transceiver board. As the radio is tuned from one frequency to another the SCRX line has a lot of activity, when the transmitter is keyed up the SCTX line has activity. Here is a sample of what is seen on the SCRX line.
 +
{| class="wikitable mw-collapsible mw-collapsed"
 +
|+
 +
!SCRX
 +
|-
 +
|J0000
 +
|-
 +
|K0000
 +
|-
 +
|G0283
 +
|-
 +
|`0
 +
|-
 +
|G1283
 +
|-
 +
|B06EE14
 +
|-
 +
|B0A03CE
 +
|-
 +
|B0C0028
 +
|-
 +
|B11E960
 +
|-
 +
|B180000
 +
|-
 +
|B140000
 +
|-
 +
|B1C2812
 +
|-
 +
|B200018
 +
|-
 +
|B280A68
 +
|-
 +
|G;7:3
 +
|-
 +
|K1900
 +
|-
 +
|a7:6
 +
|-
 +
|B1C2C12
 +
|-
 +
|B140000
 +
|-
 +
|B1C2812
 +
|-
 +
|B200018
 +
|-
 +
|B280A68
 +
|-
 +
|F41
 +
|-
 +
|J01
 +
|-
 +
|G;7:3
 +
|-
 +
|`0
 +
|}
  
 
====Understand how the radio works====
 
====Understand how the radio works====

Revision as of 02:27, 8 June 2020

Fully Assembled Kenwood TH-D74A

Teardown Video

6 minute video @ 3x playback speed showing full disassembly of the radio with commentary, full length video with no audio here.

Teardown PCB Pictures

  • Processor Board Top

  • Processor Shield Removed

  • Processor Board Bottom

  • JTAG Pinout

  • Transceiver Board Top

  • Transceiver Board Top Zoom 1

  • Transceiver Board Top Zoom 2

  • Transceiver Board Bottom

  • Transceiver Board Bottom Zoom 1

  • Transceiver Board Bottom Zoom 2

  • FM Radio Module Top

  • FM Radio Module Bottom

Modules and Interconnects

  • LCD Front

  • LCD Back

  • FM Antenna Front

  • FM Antenna Rear

  • Interconnect Top

  • Interconnect Bottom

  • Channel Selector


Mechanical Pictures

  • Front Case Interior

  • Metal Frame Front

  • Metal Frame Back

  • Metal Frame Connector Side

  • Metal Frame Button Side

  • Metal Frame Top

  • Rubber Gaskets

  • Screws and Knobs


Reverse Engineering Efforts

Kenwood TH-D74 connected to JTAGulator

High level goals

  • Obtain a copy of the firmware for analysis/modification
  • Understand how the radio works and what test ports are available internally

Obtaining firmware

  • Determine routes of attack
    • JTAG Port
    • Serial Port
    • Hardware attack - Remove Flash Memory and read directly (possibly encrypted)

Initially the radio was opened and wires were soldered to some test points and an interesting PCB footprint that I suspected was JTAG as seen in the video below.

There is also a serial port labeled SCTX and SCRX, both of these lines appear to be transmit only from the top CPU board down to the bottom transceiver board. As the radio is tuned from one frequency to another the SCRX line has a lot of activity, when the transmitter is keyed up the SCTX line has activity. Here is a sample of what is seen on the SCRX line.

SCRX
J0000
K0000
G0283
`0
G1283
B06EE14
B0A03CE
B0C0028
B11E960
B180000
B140000
B1C2812
B200018
B280A68
G;7:3
K1900
a7:6
B1C2C12
B140000
B1C2812
B200018
B280A68
F41
J01
G;7:3
`0

Understand how the radio works


Datasheets

Kenwood TH-D74A Datasheet - IC-701 - DRAM

Kenwood TH-D74A Datasheet - IC-702 - omap-l138

Kenwood TH-D74A Datasheet - IC-705 - FLASH MEMORY

IC-707 - Not exact match but same family - WM8940

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