kernel roll back

[emily_3]

After change some parameter of the current kernel and reboot the system, the system can't boot up even for single user mode. Now have boot up the system by /stand/vmunix.prev.
Can you tell me how to roll back the original kernel? Just copy back? Thanks.

[inventsekar_1]

i think this will work:
step 1: In case of bad kernel, restart the system and wait for the following message:

Processor is starting autoboot
To discontinue press a key within 10 seconds.
press any key to enter the PDC(Processor Dependant Code).

step 2: enter the boot command.
step 3: ur system will ask you if u want to interact with ISL. say "yes".
step 4: Now, at the ISL prompt, use the hpux command to boot from the old kernel

ISL> hpux /stand/vmunix.old

i am writing by reading a book. i think it will work.

[inventsekar_1 · Accepted solution]

i misunderstood and wrote only how to boot from a different kernel.

now reply,
which system u r working? (uname -a)

and for 11.23,

------------------------------------
kconfig -n config
The specified saved kernel configuration(config) is marked for use at next boot. Any
changes to the currently running configuration that are being held for next boot are
discarded.

In previous hpux versions, "kmupdate kernel"
is the command, i think.

[Arunkumar.B]

Hi Emily,

whenever if ur changing any kernel parameters it will automatically move the existing kernel to vmunix.prev.

Roll back plan

ISL>hpux /stand/vmunix.prev
#cd /stand
#cp -p vmunix vmunix.bad (Problematic kernel)
#cp -p vmunix.prev vmunix.good (Old Working )
#mv vmunix.prev vmunix

Try by rebooting

Cheers
Arunkumar

[emily_3]

Soloved this issue by using kmupdate /stand/vmunix.prev

Thanks.
Regards.