ASUS P4P800 Deluxe MB has problem detecting P-ATA HD

Hello Everyone,

I hope some of you can help me with the problem below.

My PC is configured with:

ASUS P4P800 deluxe, intel 2.4/
one S-ATA HD [ BIOS shows it as 3rd Master]
one P-ATA HD (connect to MB via mobile rack, use as data storeage, not bootable) [BIOS shows it as Primary Master]

The problem is that everytime I re-insert the P-ATA HD into the system, The BIOS automatically assumes it is the
primary drive, and try to boot with it.

Of course, it fails, the only way to fix this is to go to BIOS and change the "Boot Device Priority" to show the S-ATA is
the first choice.

However, the BIOS doesn't keep this setting. The problem repeats everytime the rack mount drive is removed and re-installed back to the system.

The problem goes away as long as the rackmount drive stays connect to the system?


Most of the setting in the BIOS are ASUS default setting.

Any idea why this happen?


TIA!

Kent