Is there a way to downgrade the BIOS. Having some issues with the latest 1.24.

Basically the SL400 will not turn off (shutdown, sleep or hibernate). It executes a restart instead of a shutdown. Have ruled out OS (tried with a Acronis boot disk, recovery OS install with no updates), am looking basically at either hardware or BIOS.

The readme for the BIOS indicates that you are unable to downgrade.
http://www-307.ibm.com/pc/support/site.wss/document.do?lndocid=MIGR-70040

Have tried to look around the ISO files with winhex to perhaps make a custom image that will downgrade to the prior release. However a bit out of my league in creating a custom firmware.

TIA..