Hello,

I revived my old 386 DX 40 computer and started to tweak the BIOS settings. I can change every setting in the BIOS with the exception of the "Timing Parameter Selection" under Advanced CMOS setup. The default for this setting is "Extended", but if I change it to "Normal" and Save & Reboot it's back to extended again. Tried new battery and loading CMOS defaults, but no luck.

The board has an AMI Bios with 5/5/1991 date and the chipset is a Symphony SL82C461. Today I tried out the AMISETUP tool and could change all the BIOS settings from DOS too. But again, when I changed the timing parameter selection to normal, it was back to extended again on next reboot.

Interestingly this guy had the same problem with a similar PC (https://groups.google.com/g/comp.os.linux.set … /m/PZmdWBZLTYEJ)

I switched the "Timing Parameter Selection" in the advanced section of the CMOS setup from "Extended" to "Normal". The built-in help describes this as "DMA timing, ROM timing(?!) and AT bus cycles(?)", with "Extended" being "worst case" and "Normal" being "best case". Extended is default.

- later, I discovered that this very option switches back to "Extended" whenever I reboot the machine.

Does anyone has an idea what this could be? Super strange that only one setting is not being save / being reverted...