I have a question in component security context.
I program my MCU from a JTAG port. I also have a secure UART device in RX to display in hyper terminal.
Can an attacker get access to secure memory and device by connecting to JTAG or via UART ?
To add to Joseph's comments on debug authentication, Arm has developed the SDC-600 secure debug channel for this purpose.
For a demonstration of how Arm debug tools use (or are locked out by) this channel, see here.