Reverse Engineering Hardware of Embedded Devices

http://blog.sec-consult.com/2017/07/reverse-engineering-hardware.html?m=1

Nowadays, we are living in a world dominated by embedded systems. Everyone can be spied on through various channels. Routers, IP-cameras, phones, and other embedded devices are affected by security vulnerabilities and are therefore easily hack-able. 
This article covers some basic hardware reverse engineering techniques on PCB-level, which are applicable to any electronic embedded device to showcase how to analyze a previously unknown (to the researcher or public white-hat community) hardware device. 
This article covers connecting to UART, JTAG and SPI interfaces. Normally we have to disassemble the device to find those debug interfaces. This process is invasive and usually leads to damaged devices.