Introduction
The N3K-C3548P-10GX is not supported below 6.0(2)A6(1) per the release notes for 6.0(2)A6(1). Currently, CCO's software download section does not delineate the PID between the 3548 and the 3548X. There is always a possibility of a image downgrade due to user error or other reasons.
A sanity check for compatible hardware (3548X/3524X) was added in 6.0(2)A6(3) which will prevent accidental downgrade to unsupported releases (pre 6.0(2)A6(1) )
Problem
For scenarios where the software running on the 3548X or 3524X is prior to 6.0(2)A6(3) and a downgrade is executed, you will see the following errors when the chassis is reloaded
POST is completed
WARNING! WARNING! WARNING! *************
####### BKPLANE SPROM CARDID NOT PROGRAMMED #########
This kickstart image is not compatible with *
the current hardware platform *
Rebooting system *
WARNING! WARNING! WARNING! *************
The switch may also drop into a infinite stack trace after reload.
Using the standard break procedure of Ctrl - ] does not work. Ctrl - c does work but loads the invalid kickstart image and breaks into the boot prompt.
Solution
In order to recover from this situation, reload the switch and use the key sequence Ctrl - L to interrupt the bios. At this point you should get the loader prompt. Boot and load a compatible kickstart/system image.