The router may begin to core-dump with the following reboot reason for the routing-engine:

This is due to a conflict between older hardware and more recent versions of BIOS in the configuration of standby mode. This article explains the issue and provides a procedure to disable standby mode.

After upgrading or replacing the compact flash on older M Series routers, the router may start to core-dump with the following routing-engine reboot reason:

The problem is due to smaller memory storage on older router hardware. By default, the following is enabled:

This is to protect the disk from continuous usage and prevent unnecessary storage usage.

In recent versions of BIOS, there is a table in smartd that houses different compact flashes and drives and is configured not to attempt standby mode with those models. Prior to these newer versions of BIOS, SSDs and compact flashes were not included in that table and as such, some models would have standby enabled by default.

When you see this message as the last reboot reason on the routing-engine:

it indicates that there is a conflict in the hard disk. The standby mode is not needed for that model of of compact flash, however it is getting enabled or "armed". This conflict is what triggers the core-dumps.

The solution to resolving this issue is to disable standby mode with the following command:

This will disable standby mode and resolve the conflict, thus stopping the core-dumps.