X86 System firmware upgradation

I have X86 level 6 ROS and installed it on IBM X3100 M4 server ,ROS version 6.20, when i trying to upgrade the firmware to latest one ( V 6.27) its downloading and asking for reboot to upgrade , But after reboot when i checked still the same 6.20 version is existing .
Kindly help me on this .

Thanks and Regards,
Sendil

Do you have a non-demo license installed on the box? Demo license does not allow for software upgrade, only complete reinstall is possible.

Otherwise, just check the logs. Whatever the reason for upgrade failure, it should be written to the log right after reboot.