JTAG, UART, SPI, fault injection, glitching, firmware reverse engineering
An advanced specialty: side-channel and physical attacks on embedded systems. UART/JTAG/SPI debug interface enumeration, firmware extraction (chip-off, bootloader exploits), Ghidra/Ida analysis of stripped firmware, voltage/clock glitching, side-channel power analysis. Recommended: AYSEC-202 (Reverse Engineering) first.