ARM, RISC-V контроллеры

может это?  http://www.atmel.com/Images/Atmel-44056-32-bit-Cortex-A5-Microcontroller-SAMA5D2_Errata.pdf
1.10 ROM Code: JTAG Access Lock Issue: When no bootable program is found on any external Flash memory, the JTAG access remains locked if the chip is not connected to a host computer using a USB connection Workaround: To re-enable the JTAG access, send any character using the UART console terminal.