External memory errors are defined as those that occur in the memory system but are not detected by the MMU. External memory errors are expected to be extremely rare and are likely to be fatal to the running processor. External aborts are caused by errors flagged by AXI when the request goes external to the processor. External aborts can be configured to trap to the monitor by setting the EA bit in the Secure Configuration Register to 1. See c1, Secure Configuration Register for more information.