Accessing And Using Grub Mode; About Grub Mode And The Configuration Register - Cisco CSR 1000v Series Software Configuration Manual

Accessing and Using GRUB Mode

•
•
•
•
•
•

About GRUB Mode and the Configuration Register

The Cisco CSR 1000v has a 16-bit configuration register in NVRAM. Each bit has value 1 (on or set) or value
0 (off or clear), and each bit setting affects the router behavior upon the next reload power cycle. The Cisco
CSR 1000v GRUB mode supports a subset of configuration register options compared to ROMMON options
on other Cisco routers.
You can use the configuration register to:
• Force the router to boot into the GRUB (bootstrap program)
• Select a boot source and default boot filename
• Recover a lost password
The table below describes the configuration register bits.
About GRUB Mode and the Configuration Register, page 221
Accessing GRUB Mode, page 223
Using the GRUB Menu, page 223
Modifying the Configuration Register (confreg), page 224
Changing the Configuration Register Settings, page 226
Displaying the Configuration Register Settings, page 227
C H A P T E R
Cisco CSR 1000v Series Cloud Services Router Software Configuration Guide
13
221