Boot Sequence - Cisco Nexus 5500 Series Configuration Manual

Image Files on the Switch

Boot Sequence

When the switch boots, the golden BIOS validates the checksum of the upgradeable BIOS. If the checksum
is valid, then control is transferred to the upgradeable BIOS image. The upgradeable BIOS launches the
kickstart image, which then launches the system image. If the checksum of the upgradeable BIOS is not valid,
then the golden BIOS launches the kickstart image, which then launches the system image.
You can force the switch to bypass the upgradeable BIOS and use the golden BIOS instead. If you press
Ctrl-Shift-6 within two seconds of when power is supplied to the switch, the golden BIOS will be used to
launch the kickstart image, even if the checksum of the upgradeable BIOS is valid.
Note When you press Ctrl-Shift-6, the console settings must be set to their defaults: 9600 baud, 8 data bits, no
parity, and 1 stop bit.
Before the boot sequence starts, the BIOS performs internal tests on the switch. If the tests fail, then the loader
does not gain control. Instead, the BIOS image retains control and prints a message to the console at 9600
baud every 30 seconds that indicates a failure.
The following figure shows the normal and recovery boot sequence.
Figure 5: Boot Sequence
Cisco Nexus 5500 Series NX-OS Fundamentals Configuration Guide, Release 7.x
14
Using the Cisco NX-OS Setup Utility
OL-30890-01