• Boot failure
• The setting of the virtual configuration register forces the router to stop in ROMmon mode during the boot
• A break sequence is sent to the console. The console will normally ignore the break, except during the boot. However, the virtual configuration register of the router may be configured to allow a break sequence at all times.

For more information about the virtual configuration register, refer to Configuration Register.

To resolve this issue, refer to the ROMmon recovery procedure that applies to your platform:

• ROMmon Recovery for the Cisco 800 Series Router
• ROMmon Recovery Procedure for the Cisco 1000 Series Router
• ROMmon Recovery for the Cisco 1600 Series Router
• ROMmon Recovery for the Cisco 1700 Series Router
• ROMmon Recovery for the Cisco 2600 Series Router and the VG200
• ROMmon Recovery for the Cisco 3600 Series Router
• ROMmon Recovery for the Cisco 4000 Series Router
• ROMmon Recovery for the Cisco 4500 and 4700 Series Routers
• ROMmon Recovery for the Cisco 2500, 3000, AS5100, and uBR900 Series Routers
• ROMmon Recovery for the AS5200 Series Router
• ROMmon Recovery Procedure for the AS5300, AS5350, and the AS5400
• ROMmon Recovery Procedure for the 7000 (RP) Series
• ROMmon Recovery Procedure for the Cisco 7200, 7300, 7400, 7500, RSP7000, Catalyst 5500 RSM, uBR7100, uBR7200, uBR10000, and 12000 Series Routers